Please answer the following question by reasoning step-by-step.
Dilation occurs when part of a cell that a what does not have relaxes.\nOptions:\n- (A) breathing\n- (B) organ\n- (C) the eyes\n- (D) abrasion\n- (E) complex\n- (F) animal\n- (G) nerves\n- (H) retina

(F)
Dilation occurs when cell walls relax.

Animals have no cell walls.

Dilation occurs when part of a cell that an animal does not have relaxes.

.

Final answer: (F)