Adult sponges are\nOptions:\n- (A) warm\n- (B) immobile\n- (C) food\n- (D) parasites\n- (E) strong\n- (F) white\n- (G) fertile\n- (H) warm-blooded
Let's think step by step below.
(B)
Adult sponges are sessile.

Sessile Attached permanently, immobile.

Adult sponges are attached permanently, immobile.

.

The final answer: (B)