beautiful coral

Corals are a large family in the phylum Coelenterata, called Anthozoa, also called "Anthozoa". They live in warm oceans and are crowded and fixed on rocks. New coral polyps grow on the dead coral skeletons. Some are branch-shaped, with graceful and flexible branches. There are stony corals that look like mushrooms; there are lithophora corals that look like human brains; there are staghorn corals that look like antlers; there are staghorn corals that look like deer antlers; Trumpet-shaped tube corals, etc., are really diverse and colorful. In fact, the various corals that people usually see are just corals.

The "housing" of the coral polyp is composed of the exoskeleton of the coral polyp. The coral polyp itself is very small. It is in the shape of a small short tube and grows fixedly on the seabed. The mouth that opens upward is both its mouth and its anus. There are many tentacles around this mouth. The tentacles of the coral are very small. The number of tentacles is Multiples of 6 or 8, therefore, corals are divided into two major categories: octocorals and hexacorals.

Its "belly" is divided into several small rooms (digestive chambers), and the number of rooms corresponds to the number of tentacles. As sea water flows through, food is brought into the digestive cavity for absorption. Coral polyps have the ability to absorb calcium from the ocean to build their skeletons. Over time, their calcareous skeletons formed coral reefs and coral islands. For example, my country's Xisha and Nansha Islands are composed of coral islands and coral reefs.

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