試題詳解

36. Given that sponges lack true tissues and organs, how do they accomplish vital functions such as gas exchange, nutrient transport, and waste disposal?
(A) They possess a gastrovascular cavity that handles all internal transport.
(B) Through specialized, but rudimentary, circulatory and excretory systems.
(C) By simple diffusion across the surfaces of their cells, which are in direct contact with the water environment.
(D) They rely on symbiotic bacteria to perform these functions for them.