Question

seawater or compressed air. a. submersibles sink when they exceed the mass of the water they displace, so vescovo used tanks to control pressure and reduce weight. b. since his submarine had to weigh more than the water it displaced to descend, vescovos vehicle relied on tanks that adjusted pressure. c. vescovos craft, which sank because it displaced more water than its mass, included tanks that adjusted internal volume. d. because a submersible must exceed the weight of the water it displaces to descend, vescovos craft used variable ballast tanks that adjusted its buoyancy by filling with seawater or compressed air.

Explanation:

According to Archimedes' principle, a submersible descends when its weight exceeds the buoyant - force (weight of the displaced water). Variable ballast tanks can adjust buoyancy by filling with seawater (increasing weight) or compressed air (decreasing weight). Option D correctly describes this concept. Option A is wrong as it mentions controlling pressure and reducing weight in a less accurate way related to sinking. Option B only mentions pressure adjustment without the key concept of buoyancy adjustment through ballast. Option C has an incorrect statement about the relationship between the mass of the craft and the water it displaces for sinking.

Answer:

D. Because a submersible must exceed the weight of the water it displaces to descend, Vescovo's craft used variable ballast tanks that adjusted its buoyancy by filling with seawater or compressed air.