In a certain code language, 'FLOWER' is coded as 'RFOELW', then 'ANIMAL' will be written as:

Let's analyze the positions of letters in 'FLOWER' numbered from $1$ to $6$:
$${\text{F}}_1{\text{L}}_2{\text{O}}_3{\text{W}}_4{\text{E}}_5{\text{R}}_6$$

The coded form is 'RFOELW'. Let's match the positions:

$${\text{R}}_6{\text{F}}_1{\text{O}}_3{\text{E}}_5{\text{L}}_2{\text{W}}_4$$

The rearrangement pattern is positions: $6,1,3,5,2,4$.
Applying this to 'ANIMAL':

$${\text{A}}_1{\text{N}}_2{\text{I}}_3{\text{M}}_4{\text{A}}_5{\text{L}}_6$$

Rearranging in the pattern $6,1,3,5,2,4$:

* Position 6: L
* Position 1: A
* Position 3: I
* Position 5: A
* Position 2: N
* Position 4: M
Thus, the code is 'LAIANM'.