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The phylum whose members have a notochord, a nerve cord, and slits in their throat area at some point in their lives.
An animal whose body regulates its own temperature by controlling the internal heat it produces.
An internal gas-filled organ that helps a bony fish stabilize its body at different water depths.
An organ found in air-breathing vertebrates that exchanges oxygen and carbon dioxide with the blood.
An egg with a shell and internal membranes that keep the embryo moist; a major adaptation to life on land, characteristic of reptiles, birds, and egg-laying mammals.
A scientist who studies extinct organisms, examines fossil structure, and makes comparisons to present-day organisms.
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