Old blooded animals modulate the fatty acid composition of their membranes as a function of temperature in order to A) ensure consistent membrane fluidity. B) maximize available fatty acids for metabolic use. C) adjust the membrane thickness and increase thermal insulation. D) compensate for decreasing cholesterol solubility. E) all of the above

In order to ensure consistent membrane fluidity

Explanation:

Cold-blooded animals rely on the temperature of the surrounding environment to maintain its internal temperature, their blood is not cold.  Their body temperature fluctuates,  based on the external temperature of the environment. If it  is 30 °F outside, their body temperature  will eventually normalize to  30 °F, as well. If it eventually rises to 120 °F, their body temperature will follow the same pattern to 120 °F.

The cell membrane of cold-blooded animals contains cholesterol, which acts as a shield for the membrane. Membrane fluidity is enhanced by temperature, as the temperature increases membrane fluidity increases and it decreases when the temperature goes down.

Most cold-blooded animals adjust their feeding habit to contain  more unsaturated fats from plants. This helps them to maintain their motor coordination and membrane fluidity during the long winter

Cold-blooded animals modulate the fatty acid composition of their membrane to stabilize their membrane fluidity

it is the most commonly accepted one

the answer is option a.