SSC Selection Post 2024 Higher Secondary Level Question Paper (25-Jun-2024) (Shift4)

Select the option that is related to the third word in the same way as the second word is related to the first word.
(The words must be considered as meaningful English words and must not be related to each other based on the number of letters/number of consonants/vowels in the word)
Eye : Tears :: Skin : ?

Select the Venn diagram that best illustrates the relationship between the following classes.
Lion, Dog, Elephant

Select the option that represents the letters that, when sequentially placed from left to right in the blanks below, will complete the letter series.
C _ C _ S _ C _ _ C _ _

Select the correct mirror image of the given figure when the mirror is placed at line MN as shown to its right.

Select the correct option that indicates the arrangement of the following words in a logical and meaningful order.
District

Room

Village

State

House

Select the combination of letters that when sequentially placed in the blanks of the given series will complete the series.
_ NE CIN _ C _ M

In a certain code language, 'PAST' is coded as '9713' and 'SORE' is coded as '8146'. What is the code for 'S' in that language?

In a certain code language, 'NOISE' is coded as 124 and 'WILD' is coded as 96. How will 'GIVER' be coded in the same language?

In this question, three statements are given, followed by two conclusions numbered I and II. Assuming the statements to be true, even if they seem to be at variance with commonly known facts, decide which of the conclusions logically follows/follow from the statements.
Statements:
I. Some digits are alphabets.
II. All alphabets are books.
III. Some books are novels.

Conclusions:
I. All novels are digits.
II. Some digits are books.

In a certain code language,
‘A + B’ means ‘A is the mother of B’,

‘A – B’ means ‘A is the father of B’,

‘A × B’ means ‘A is the daughter of B’.

Based on the above, how is H related to L if ‘H + I – J × K + L’?

Select the figure from among the given options that can replace the question mark (?) in the following series.

Select the option that is related to the fifth letter cluster in the same way as the second letter cluster is related to the first letter cluster and the fourth letter cluster is related to the third letter cluster.
DIALOGUE: HMEPKCQA :: HOSPITAL: LSWTEPWH :: CHAMBERS : ?

In a certain code language,
‘A + B’ means ‘A is the wife of B’

‘A – B’ means ‘A is the sister of B’

‘A × B’ means ‘A is the mother of B’

‘A ÷ B’ means ‘A is the daughter of B’

Based on the above, how is O related to L if ‘O − M ÷ N + L’?

In a certain code language, 'THORP' is written as 'IUNKM' and 'SERIES' is written as 'JXKTXJ'. How will 'TRACE' be written in that language?

Select the option that is related to the third word in the same way as the second word is related to the first word.
(The words must be considered as meaningful English words and must not be related to each other based on the number of letters/number of consonants/vowels in the word)
Cow : Bull :: Mare : ?

Two Statements are given followed by Three conclusions numbered I, II and III. Assuming the statements to be true, even if they seem to be at variance with commonly known facts, decide which of the conclusions logically follow(s) from the statements.
Statements:

Some mugs are rugs.

All tugs are mugs.

Conclusions:
I. Some rugs are mugs.
II. Some mugs are tugs.
III. No rug is a mug.

Select the option figure in which the given question figure is embedded as its part (Rotation is NOT allowed).

Select the option that represents the correct order of the given words as they would appear in an English dictionary.
Masterstroke

Malnutrition

Marigold

Magical

Magnify

In a certain code language, 'BUSHY' is written as 'CTTGZ' and 'COAST' is written as 'DNBRU'. How will 'DWELL' be written in that language?

The numbers in each set are related to each other in a certain way.
(2, 12, 72), (7, 42, 252), (4, 24, ?)

Based on the relationship among the numbers in the first two sets, select the number that can replace the question mark (?) in the third set.

If ‘A’ stands for ‘÷ Gentile division’, ‘B’ stands for ‘×’, ‘C’ stands for ‘+’ and ‘D’ stands for ‘−’, what will come in place of the question mark (?) in the following equation?
36 B 17 D 59 C 224 A 7 = ?

Six numbers 1, 2, 3, 4, 5 and 6 are written on different faces of a dice. Two positions of this dice are shown. (Position 1 shows faces 1, 4, 6 and Position 2 shows faces 3, 5, 6 with 6 being common on the top face). Find the number on the face opposite to 2.

Select the correct option that indicates the arrangement of the following words in a logical and meaningful order.
Toddler

Adult

Adolescent

Foetus

Baby

Select the number from among the given options that can replace the question mark (?) in the following series.
729, 512, 343, ?, 125

In a certain code language,
‘M & N’ means ‘M is the mother of N’

‘M @ N’ means ‘M is the son of N’,

‘M # N’ means ‘M is the daughter of N’.

Based on the above, how is L related to O if ‘K & L & M # N @ O’?

Which Article of the Indian Constitution makes it clear that Directive Principles of State Policy are fundamental in the governance of the country and it shall be the duty of the state to apply these principles in making laws?

Which of the following festivals is also known as the '100 drums festival'?

Who among the following is the author of the book 'The Complete Adventures of Feluda'?

Which triangular plateau region of India lies south of the river Narmada?

Who among the following Mauryan rulers was the first, who tried to convey his messages to his subjects concerning the idea and practice of dhamma through inscriptions?

The ministers in the state hold office during the pleasure of the:

AIDS is an abbreviation for:

Under the Governor Generalship of ______, the Permanent Settlement was introduced in 1793.

Chromosomes found in the salivary glands of Drosophila are:

Pradhan Mantri Virasat Ka Samvardhan (PM VIKAS) Scheme is a scheme of which Ministry of the Government of India?

In which of the following festivals is Kolam drawn?

The Vikramshila University was founded under the patronage of the king ______.

What is the percentage of people below the poverty line in India according to Government of India, planning commission 2013?

Through an Act passed in which year was the post of Governor-General removed and a new post of Viceroy got created during British rule in India?

Which of the following options is INCORRECT?
In order to become a member of Vidhan Sabha, a person must:

Lad Khan Temple at Aihole in Karnataka is an example of which of the following styles of temple architecture?

Which of the following does NOT come under the Concurrent List?

A ______ is one billionth of a metre.

Padma Shri Awardee Gosaveedu Shaik Hassan is known for playing:

Who among the following was appointed as the Chairman of the 22
nd
Law Commission in November 2022?

______ is the study of the distribution and movement of water both on and below the Earth's surface, as well as the impact of human activity on water availability and conditions.

In February 2023, which State Government's cabinet has approved the new excise policy under which 'ahatas', or areas for drinking attached to liquor outlets, and shop bars will be closed?

Who among the following Hindustani classical musicians was NOT associated with 'Maihar Gharana'?

In which of the following years was the first population census conducted non-synchronously in different parts of India?

Which is the deepest point of Earth's oceans with a depth of 11,022 metres?

$△ABC$ and $△ABD$ are on a common base $AB$, with $AC=BD$ and $BC=AD$. Which of the following options is true?

A person spends $60\%$ of his income. His income increased by $30\%$ and he increased his expenditure by $20\%$. His percent savings will then be increased by:

A shopkeeper announced a $17\%$ rebate on the marked price of an article. If the selling price of the article is ₹$1,245$, then the marked price (in ₹) of the article is:

A train leaves Hyderabad at 4:00 A.M. and reaches Vijayawada at 8:00 A.M. the same day. Another train leaves Vijayawada at 6:00 A.M. and reaches Hyderabad at 9:30 A.M the same day. At what time do the two trains cross each other?

A shopkeeper mixes $15\text{ kg}$ of sugar costing ₹$11/\text{kg}$ with $22\text{ kg}$ of sugar costing ₹$12/\text{kg}$. What is the cost (in ₹) per kg of the mixture? (Rounded off to 2 decimal places)

If a car covers $90\text{ km}$ using $4$ litres of petrol, how much distance (in km) will it cover using $32$ litres of petrol?

The given pie chart displays the number of patients who come to a clinic per week, for treatment under various heads. The total number of patients who come to the clinic is $4060$ per week. Study the pie chart and answer the question that follows.(Note: Since percentages/degrees values are typically proportional, we can compute directly using their standard standard values for this question where Trauma + Dexa + Blood works = $150^{\circ }$ and OPD + X-ray + Physiotherapy = $210^{\circ }$, or equivalent values leading to the exact percentage)The combined number of patients for the treatment of trauma, dexa and blood works is what percentage (rounded off to 1 decimal place) more or less than the combined number of patients for OPD, X-ray and physiotherapy?

Evaluate:
$${\left(\frac{\sin 23^{\circ }\cos 67^{\circ }+\cos 23^{\circ }\sin 67^{\circ }}{{\mathrm{cosec}}^{2}15^{\circ }-{\tan }^{2}75^{\circ }}\right)}^3$$

In $△OPQ$, $\angle O=50^{\circ }$, $\angle P=70^{\circ }$, and the bisectors of $\angle P$ and $\angle Q$ meet at $R$. Find $\angle PRQ$.

The following table shows the number of medals won by four boys in different activities.Name of Boy / ActivityYogaSwimmingDanceSingingRamagya24283233Bitthal28302928Rameshwar35293830Krishna29343136Who won more medals in swimming than in singing?

A sphere and a cube have equal surface areas. The ratio of the volume of the sphere to that of the cube is:

A vendor buys $20$ pens for ₹$15$ and sells them at $15$ for ₹$20$. How many pens should be bought and sold to earn a profit of ₹$245$?

A can do a piece of work in $25$ days. After working for $5$ days, he took help of B and completed the work in $8$ days. If both A and B had worked together from the beginning, in how many days would they have completed the work?

Sarthak and Mohan are working on alternate days in a workshop. Sarthak can complete the work in $20$ days while Mohan can finish in $25$ days. Sarthak works on the 1st day, Mohan on the 2nd day, and so on. How much time (in days) will they take on alternate basis?

The following bar graph shows the failure rates (in thousands) for different electric components:How many times is the failure rate of hybrid micro circuits compared to that of signal devices?

A shopkeeper normally makes a profit of $20\%$ in a certain transaction; he weighed $900\text{ gm}$ instead of $1\text{ kg}$ due to an error in the weighing machine. If he charges $15\%$ less than what he normally charges, then what is his actual profit or loss percentage?

Two numbers are in the ratio $4:5$. If $17$ is subtracted from each, the new numbers are in the ratio $11:14$. If $20$ is added to each of the original numbers, then the ratio becomes:

In a division sum, the divisor is $10$ times the quotient and $5$ times the remainder. If the remainder is $12$, then what is the dividend?

If $(x+y+z)=23$ and $x^2+y^2+z^2=179$, then find the value of $(xy+yz+zx)$.

In what duration (in years) will ₹$1,500$ amount to ₹$2,250$ at simple interest $10\%$ per annum?

Which of the following numbers will completely divide $4^{12}+4^{13}+4^{14}+4^{15}$?

If $x+\frac{1}{x}=7$, find the value of $x^3+\frac{1}{x^3}$.

The prices of a school bag and a school dress are in the ratio of $8:7$. The price of the school bag is ₹$400$ more than the price of the school dress. Find the price of the school dress.

A person mixes two liquids, $x$ and $y$. One litre of $x$ weighs approximately $900\text{ g}$, and one litre of $y$ weighs approximately $750\text{ g}$. If one litre of the mixture weighs approximately $800\text{ g}$, then the percentage of $x$ in the mixture is:

In a circular race of $2,500\text{ m}$, Reeta and Geeta start running in the same direction from the same point and at the same time with speeds of $36\text{ km/h}$ and $54\text{ km/h}$, respectively. After how much time will they meet for the first time on the track?

Select the most appropriate ANTONYM of the underlined word in the given sentence.
A few minutes later a request came that all members of the house party should assemble in the drawing-room.

Select the sentence that does NOT have a spelling error.

Select the option that expresses the following sentence in active voice.
Were these books bought by her yesterday?

The following sentence has been divided into parts. One of them may contain an error. Select the part that contains the error from the given options. If you don't find any error, mark 'No error' as your answer.
By the time she retires, / she has been teaching / at the university for 30 years.

Select the most appropriate meaning of the given idiom.
Rohit laid down his proposal, and told Rohit that the ball was now in his court.

Select the option that can be used as a one-word substitute for the given group of words.
Beliefs or incidents that happen in a way which cannot be explained by reason or science.

Select the option that can be used as a one-word substitute for the given group of words.
A person who renounces a religious or political belief or principle.

Select the option that expresses the given sentence in passive voice.
We love Nathan.

Select the option that expresses the given sentence in active voice.
A Mercedes-Benz was owned by my father.

Select the option that expresses the given sentence in indirect speech.
He said, "She has finished the painting."

Select the INCORRECTLY spelt word.

Select the most appropriate article to fill in the blank.
Your shirt is ______ same colour as mine.

Select the option that can be used as a one-word substitute for the given group of words.
Crime of killing a king

Select the most appropriate meaning of the given idiom.
To make both ends meet

Select the option that can be used as a one-word substitute for the given group of words.
A study of the conditions and structure of the earth

In the following passage, some words have been deleted. Read the passage carefully and select the most appropriate option to fill in each blank.
The water cycle, also known as the hydrological cycle, is a continuous process that circulates water throughout the Earth's systems. It involves the movement of water between the (1) ______ the water bodies and the land. The cycle consists of several key stages, each playing a crucial role in maintaining Earth's water balance.
At the heart of the water cycle is the process of (2) ______. This is where water from oceans, lakes and rivers is heated by the sun and turns into water vapour. This water vapour then rises into the atmosphere, where it cools and condenses to form clouds. When these clouds become heavy enough, they release their moisture through (3) ______ which can fall as rain or other forms of precipitation.
When precipitation falls onto the land, it can take different paths. Some of it may evaporate back into the air, while some may be taken up by plants and released back into the atmosphere through a process called (4) ______. The rest of the water may flow over the land's surface, gathering in streams and rivers that eventually lead back to the oceans, completing the cycle.
The water cycle is essential for maintaining Earth's ecosystems and supporting life. It helps distribute fresh water to various regions, replenishes water sources, and plays a role in regulating (5) ______ temperatures. Understanding the water cycle is crucial for addressing water scarcity and managing natural resources effectively.

Select the most appropriate option to fill in blank number 1.

In the following passage, some words have been deleted. Read the passage carefully and select the most appropriate option to fill in each blank.
The water cycle, also known as the hydrological cycle, is a continuous process that circulates water throughout the Earth's systems. It involves the movement of water between the (1) ______ the water bodies and the land. The cycle consists of several key stages, each playing a crucial role in maintaining Earth's water balance.
At the heart of the water cycle is the process of (2) ______. This is where water from oceans, lakes and rivers is heated by the sun and turns into water vapour. This water vapour then rises into the atmosphere, where it cools and condenses to form clouds. When these clouds become heavy enough, they release their moisture through (3) ______ which can fall as rain or other forms of precipitation.
When precipitation falls onto the land, it can take different paths. Some of it may evaporate back into the air, while some may be taken up by plants and released back into the atmosphere through a process called (4) ______. The rest of the water may flow over the land's surface, gathering in streams and rivers that eventually lead back to the oceans, completing the cycle.
The water cycle is essential for maintaining Earth's ecosystems and supporting life. It helps distribute fresh water to various regions, replenishes water sources, and plays a role in regulating (5) ______ temperatures. Understanding the water cycle is crucial for addressing water scarcity and managing natural resources effectively.

Select the most appropriate option to fill in blank number 2.

In the following passage, some words have been deleted. Read the passage carefully and select the most appropriate option to fill in each blank.
The water cycle, also known as the hydrological cycle, is a continuous process that circulates water throughout the Earth's systems. It involves the movement of water between the (1) ______ the water bodies and the land. The cycle consists of several key stages, each playing a crucial role in maintaining Earth's water balance.
At the heart of the water cycle is the process of (2) ______. This is where water from oceans, lakes and rivers is heated by the sun and turns into water vapour. This water vapour then rises into the atmosphere, where it cools and condenses to form clouds. When these clouds become heavy enough, they release their moisture through (3) ______ which can fall as rain or other forms of precipitation.
When precipitation falls onto the land, it can take different paths. Some of it may evaporate back into the air, while some may be taken up by plants and released back into the atmosphere through a process called (4) ______. The rest of the water may flow over the land's surface, gathering in streams and rivers that eventually lead back to the oceans, completing the cycle.
The water cycle is essential for maintaining Earth's ecosystems and supporting life. It helps distribute fresh water to various regions, replenishes water sources, and plays a role in regulating (5) ______ temperatures. Understanding the water cycle is crucial for addressing water scarcity and managing natural resources effectively.

Select the most appropriate option to fill in blank number 3.

In the following passage, some words have been deleted. Read the passage carefully and select the most appropriate option to fill in each blank.
The water cycle, also known as the hydrological cycle, is a continuous process that circulates water throughout the Earth's systems. It involves the movement of water between the (1) ______ the water bodies and the land. The cycle consists of several key stages, each playing a crucial role in maintaining Earth's water balance.
At the heart of the water cycle is the process of (2) ______. This is where water from oceans, lakes and rivers is heated by the sun and turns into water vapour. This water vapour then rises into the atmosphere, where it cools and condenses to form clouds. When these clouds become heavy enough, they release their moisture through (3) ______ which can fall as rain or other forms of precipitation.
When precipitation falls onto the land, it can take different paths. Some of it may evaporate back into the air, while some may be taken up by plants and released back into the atmosphere through a process called (4) ______. The rest of the water may flow over the land's surface, gathering in streams and rivers that eventually lead back to the oceans, completing the cycle.
The water cycle is essential for maintaining Earth's ecosystems and supporting life. It helps distribute fresh water to various regions, replenishes water sources, and plays a role in regulating (5) ______ temperatures. Understanding the water cycle is crucial for addressing water scarcity and managing natural resources effectively.

Select the most appropriate option to fill in blank number 4.

In the following passage, some words have been deleted. Read the passage carefully and select the most appropriate option to fill in each blank.
The water cycle, also known as the hydrological cycle, is a continuous process that circulates water throughout the Earth's systems. It involves the movement of water between the (1) ______ the water bodies and the land. The cycle consists of several key stages, each playing a crucial role in maintaining Earth's water balance.
At the heart of the water cycle is the process of (2) ______. This is where water from oceans, lakes and rivers is heated by the sun and turns into water vapour. This water vapour then rises into the atmosphere, where it cools and condenses to form clouds. When these clouds become heavy enough, they release their moisture through (3) ______ which can fall as rain or other forms of precipitation.
When precipitation falls onto the land, it can take different paths. Some of it may evaporate back into the air, while some may be taken up by plants and released back into the atmosphere through a process called (4) ______. The rest of the water may flow over the land's surface, gathering in streams and rivers that eventually lead back to the oceans, completing the cycle.
The water cycle is essential for maintaining Earth's ecosystems and supporting life. It helps distribute fresh water to various regions, replenishes water sources, and plays a role in regulating (5) ______ temperatures. Understanding the water cycle is crucial for addressing water scarcity and managing natural resources effectively.

Select the most appropriate option to fill in blank number 5.

Read the given passage and answer the questions that follow.
Our failure to control one of the most common of all ailments sometimes seems ridiculous. Medical science regularly practises transplant surgery and has rid whole countries of such killing diseases as Typhus and the Plague. But the problem of the common cold is unusually difficult and much has yet to be done to solve it. It is known that a cold is caused by one of a number of viral infections that affect the lining of the nose and other passages leading to the lungs, but the confusing variety of viruses makes studying and remedy very difficult. It was shown in 1960 that many typical colds in adults are caused by one or the other of a family of viruses known as rhinoviruses, yet there still remain many colds for which no virus has as yet been isolated.
There is also the difficulty that, because they are so much smaller than the bacteria which cause many other infections, viruses cannot be seen with ordinary microscopes. Nor can they be cultivated easily in the bacteriologist's laboratory, since they only grow within the living cells of animals or plants. An important recent step forward, however, is the development of the technique of tissue culture, in which bits of animal tissue are enabled to go on living and to multiply independently of the body. This has greatly aided virus research and has led to the discovery of a large number of viruses. Their existence had previously been not only unknown but even unsuspected. The fact that we can catch a cold repeatedly creates another difficulty. Usually, a virus strikes only once and leaves the victim immune to further attacks. Still, we do not gain immunity from colds. It seems, therefore, that we are likely to have to suffer colds for some time yet.

Identify the most suitable inference from the given passage.

Read the given passage and answer the questions that follow.
Our failure to control one of the most common of all ailments sometimes seems ridiculous. Medical science regularly practises transplant surgery and has rid whole countries of such killing diseases as Typhus and the Plague. But the problem of the common cold is unusually difficult and much has yet to be done to solve it. It is known that a cold is caused by one of a number of viral infections that affect the lining of the nose and other passages leading to the lungs, but the confusing variety of viruses makes studying and remedy very difficult. It was shown in 1960 that many typical colds in adults are caused by one or the other of a family of viruses known as rhinoviruses, yet there still remain many colds for which no virus has as yet been isolated.
There is also the difficulty that, because they are so much smaller than the bacteria which cause many other infections, viruses cannot be seen with ordinary microscopes. Nor can they be cultivated easily in the bacteriologist's laboratory, since they only grow within the living cells of animals or plants. An important recent step forward, however, is the development of the technique of tissue culture, in which bits of animal tissue are enabled to go on living and to multiply independently of the body. This has greatly aided virus research and has led to the discovery of a large number of viruses. Their existence had previously been not only unknown but even unsuspected. The fact that we can catch a cold repeatedly creates another difficulty. Usually, a virus strikes only once and leaves the victim immune to further attacks. Still, we do not gain immunity from colds. It seems, therefore, that we are likely to have to suffer colds for some time yet.

The most appropriate synonym of the word 'isolated' is:

Read the given passage and answer the questions that follow.
Our failure to control one of the most common of all ailments sometimes seems ridiculous. Medical science regularly practises transplant surgery and has rid whole countries of such killing diseases as Typhus and the Plague. But the problem of the common cold is unusually difficult and much has yet to be done to solve it. It is known that a cold is caused by one of a number of viral infections that affect the lining of the nose and other passages leading to the lungs, but the confusing variety of viruses makes studying and remedy very difficult. It was shown in 1960 that many typical colds in adults are caused by one or the other of a family of viruses known as rhinoviruses, yet there still remain many colds for which no virus has as yet been isolated.
There is also the difficulty that, because they are so much smaller than the bacteria which cause many other infections, viruses cannot be seen with ordinary microscopes. Nor can they be cultivated easily in the bacteriologist's laboratory, since they only grow within the living cells of animals or plants. An important recent step forward, however, is the development of the technique of tissue culture, in which bits of animal tissue are enabled to go on living and to multiply independently of the body. This has greatly aided virus research and has led to the discovery of a large number of viruses. Their existence had previously been not only unknown but even unsuspected. The fact that we can catch a cold repeatedly creates another difficulty. Usually, a virus strikes only once and leaves the victim immune to further attacks. Still, we do not gain immunity from colds. It seems, therefore, that we are likely to have to suffer colds for some time yet.

Select the most suitable title for the given passage.

Read the given passage and answer the questions that follow.
Our failure to control one of the most common of all ailments sometimes seems ridiculous. Medical science regularly practises transplant surgery and has rid whole countries of such killing diseases as Typhus and the Plague. But the problem of the common cold is unusually difficult and much has yet to be done to solve it. It is known that a cold is caused by one of a number of viral infections that affect the lining of the nose and other passages leading to the lungs, but the confusing variety of viruses makes studying and remedy very difficult. It was shown in 1960 that many typical colds in adults are caused by one or the other of a family of viruses known as rhinoviruses, yet there still remain many colds for which no virus has as yet been isolated.
There is also the difficulty that, because they are so much smaller than the bacteria which cause many other infections, viruses cannot be seen with ordinary microscopes. Nor can they be cultivated easily in the bacteriologist's laboratory, since they only grow within the living cells of animals or plants. An important recent step forward, however, is the development of the technique of tissue culture, in which bits of animal tissue are enabled to go on living and to multiply independently of the body. This has greatly aided virus research and has led to the discovery of a large number of viruses. Their existence had previously been not only unknown but even unsuspected. The fact that we can catch a cold repeatedly creates another difficulty. Usually, a virus strikes only once and leaves the victim immune to further attacks. Still, we do not gain immunity from colds. It seems, therefore, that we are likely to have to suffer colds for some time yet.

Medical science has not done anything yet to solve the problem of the common cold because:

Read the given passage and answer the questions that follow.
Our failure to control one of the most common of all ailments sometimes seems ridiculous. Medical science regularly practises transplant surgery and has rid whole countries of such killing diseases as Typhus and the Plague. But the problem of the common cold is unusually difficult and much has yet to be done to solve it. It is known that a cold is caused by one of a number of viral infections that affect the lining of the nose and other passages leading to the lungs, but the confusing variety of viruses makes studying and remedy very difficult. It was shown in 1960 that many typical colds in adults are caused by one or the other of a family of viruses known as rhinoviruses, yet there still remain many colds for which no virus has as yet been isolated.
There is also the difficulty that, because they are so much smaller than the bacteria which cause many other infections, viruses cannot be seen with ordinary microscopes. Nor can they be cultivated easily in the bacteriologist's laboratory, since they only grow within the living cells of animals or plants. An important recent step forward, however, is the development of the technique of tissue culture, in which bits of animal tissue are enabled to go on living and to multiply independently of the body. This has greatly aided virus research and has led to the discovery of a large number of viruses. Their existence had previously been not only unknown but even unsuspected. The fact that we can catch a cold repeatedly creates another difficulty. Usually, a virus strikes only once and leaves the victim immune to further attacks. Still, we do not gain immunity from colds. It seems, therefore, that we are likely to have to suffer colds for some time yet.

Which of the following is the most appropriate summary of the given passage?