Answer:
Description below
Explanation:
Alcionaceans (Alcyonacea) is an order of corals that belongs to the subclass Octocorallia, of the Anthozoa class. <em>Soft corals</em> are commonly called, since they do not produce skeletons of calcium carbonate, so they do not contribute to the construction of the reefs, although they inhabit them.
The so-called soft corals and leather or leather corals, mostly meaty in appearance, have microscopic crystals of calcite in their tissues called spicules, whose function is to give consistency to the animal's tissue, in the absence of a skeleton. The shape and distribution of the spicules are the main characteristics used in the identification of genera and species of octocorals.
In addition to soft corals, this order includes gorgonians, which replace the skeleton of hard corals, Scleractinia order, by semi-rigid structures composed of calcite and / or a substance they generate called gorgonin.
The vertebrate endoskeleton is internal while an arthropod's exoskeleton is not
Answer:
when carbon dioxide level goes up.temp. goes down.and vice versa
Answer:
Let's complete the question by writing the sequence, from earliest to most recent options
a. 2 → 1 → 3 → 4
b. 2 → 4 → 3 → 1
c. 2 → 3 → 1 → 4
d. 2 → 1 → 4 → 3
e. 2 → 4 → 1 → 3
It's surely going to be e.
e. 2 → 4 → 1 → 3
2. Cambrian explosion occurs.
4. Vertebrates become top predators in the seas.
1. Protostomes invade terrestrial environments.
3. Deuterostomes invade terrestrial environments.
Got it!
The answer is cnidaria
hope this helps :)