Read the following four statements (A – D):(A) Both, photophosphorylation and oxidative phosphorylation involve uphill transport of protons across the membrane.(B) In dicot stems, a new cambium originates from cells of pericycle at the time of secondary growth.(C) Stamens in flowers of Gloriosa and Petunia are polyandrous.(D) Symbiotic nitrogen-fixers occur in free-living state also in soil.How many of the above statements are right?

* (A) Correct: Both processes use an electron transport chain to pump protons (uphill transport) against a concentration gradient to create a proton motive force.(B) Incorrect: In dicot stems, the vascular cambium originates from intrafascicular and interfascicular cambium. The cork cambium (phellogen) usually develops in the cortex. Pericycle-origin cambium is characteristic of roots.(C) Correct: Polyandrous means stamens are free. Gloriosa (Liliaceae) and Petunia (Solanaceae) have free stamens.(D) Correct: Rhizobium lives as a free-living aerobe in soil but fixes nitrogen only as a symbiont.Three statements (A, C, D) are correct.