hydrosphere & oceanography section 3 MCQ Questions & Answers Detailed Explanation

Answer: (c)

Answer: (d)

The term “coral reef” generally refers to a marine ecosystem in which the main organisms are corals that house algal symbionts within their tissues.

These ecosystems require:

1. fully marine waters;
2. warm temperatures; and
3. ample sunlight.

They are therefore restricted to shallow waters of tropical and subtropical regions.

Answer: (d)

A strait is a narrow, typically navigable channel of water that connects two larger, navigable bodies of water.

It most commonly refers to a channel of water that lies between two landmasses, but it may also refer to a navigable channel through a body of water that is otherwise not navigable, for example, because it is too shallow, or because it contains an unnavigable reef or archipelago.

Answer: (a)

Answer: (d)

Answer: (c)

Corals are mainly found in the tropical oceans. Corals need clean sediment-free water. A coral polyp has a sack-like body and an opening encircled by stinging tentacles called cnidae.

The coral polyp uses calcium carbonate from seawater to build itself a hard skeleton and it is this limestone skeleton that protects the soft coral polyp.