In Studying a Species of Fish, a Structure Is Discovered

question 3

Multiple Choice

In studying a species of fish, a structure is discovered that has no apparent function. If this is a vestigial structure, what should be found in some relatives of this fish?

• A) The structure should be absent.
• B) A similar structure should be present, but it would be larger and have a function.
• C) The structure should look different and also have no function.
• D) The structure should be absent from fossils of ancestors of this species.

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Definitions:

Parathyroid Hormone

A hormone released by the parathyroid glands important for maintaining a stable level of calcium in the blood.

Insulin

A hormone produced by the pancreas that regulates the amount of glucose in the blood.

Neurosecretory Cell

Specialized neuron that secretes a hormone into the blood in response to an action potential.

Action Potential

A temporary reversal of an electric membrane potential, allowing for signal conduction in neurons.