Which is immobile?\nOptions:\n- (A) adult starfish\n- (B) all matter\n- (C) adult goldfish\n- (D) gastropod shells\n- (E) tadpoles\n- (F) adult sponges\n- (G) an object\n- (H) an organism's body
Let's be accurate as possible and think first.
(F)
Adult sponges are sessile.

Sessile Attached permanently, immobile.

Adult sponges are immobile.

.

Therefore, the answer is (F)