Question

1. what structure quickly shoots water out to propel a mollusk forward in water?

trochophore
radula
siphon
coelom

Explanation:

To solve this, we analyze each option:

• Trochophore: A larval form of some mollusks, not for propulsion.
• Radula: A feeding structure (like a tongue with teeth) in mollusks, not for movement.
• Siphon: In mollusks (e.g., squids, octopuses), water is expelled from the siphon to propel forward (jet propulsion).
• Coelom: A body cavity, not a structure for propulsion.

So the siphon is the structure that shoots water to propel a mollusk.

Answer:

C. siphon