Answer:
D
an increase in the length of the fatty acid tails.
Step-by-step explanation:
As average annual temperatures decrease, we would expect to find phospholipids within the cell membranes of organisms to have both saturated
and unsaturated fatty acid tails. Saturated fatty acids tails are arranged linearly, in a way that maximizes interactions between the tails and
decreases bilayer fluidity. Unsaturated fatty acids, on the other hand, have more distance between the tails, fewer intermolecular interactions and
more membrane fluidity. Longer tails and decreased cholesterol also decrease fluidity