Tiny marine Animals which constitute limestone skeletons are called

A. Coral Reefs

B. Diatoms

C. Clamitomonous

D. Foraminifer

Ans. (A) Coral Reefs

Explanation:

Coral reefs are massive structures made of limestone deposited by living things. Although thousands of species inhabit coral reefs, only a fraction produce the limestone that builds the reef. The most important reef-building organisms are the corals.

Although there are hundreds of different species of corals, they are generally classified as either hard coral or soft coral.

Hard corals grow in colonies and are the architects of coral reefs. Including such species as brain coral and elkhorn coral, hard coral create skeletons out of calcium carbonate (also known as limestone), a hard substance that eventually becomes rock.