Let's think step by step! What produces both eggs and sperm?
Options:
- (A) Plant reproduction
- (B) sub-units of species
- (C) gastropod shells
- (D) an individual mature sponge
- (E) Microscopic organisms
- (F) members of their own species
- (G) peachleaf willow
- (H) seed dispersal
The thinking starts now:
Adult sponges produce eggs and sperm. An adult is mature, fully developed. Mature sponges produce eggs and sperm. The final answer: (D).