Answer:
during the Cambrian Period of the Paleozoic Era.
Explanation:
The Paleozoic is the earliest era (of three) of the Phanerozoic Eon and is composed of six geologic periods: the Cambrian, Ordovician, Silurian, Devonian, Carboniferous, and Permian (in that order from earliest to the latest). Fish first appeared about 530 million years ago during the Cambrian explosion.
A because if you are going down deeper into the ocean, you are going farther away from the sun so it will become colder.
hardness<span>, </span>luster<span>, </span>color<span>, </span>streak<span>, </span>specific gravity<span>, </span>cleavage<span>, fracture, and </span>tenacity<span>.</span>
Muscles connect to your<span> skeleton and they contract and </span>move the skeleton along.<span> The calcified bones of </span>your<span> skeleton also work with the circulatory </span>system<span>.
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Answer: cellular respiration
Explanation: I hope this helps