Answer:
Index fossil that is also known as indicator fossil is used to determine the age of the layers of the rocks. It says that the new layer of sedimentary rocks lie over the old layer.
The deeper we go, the older the rocks we will find. Index fossil of animals that lived or survived only for a short period of time are very useful. An example of index fossil can be Ammonites that were found in Mesozoic era that was about 25-35 million years ago.
Answer: I believe the Lateral Lines are made of mechanoreceptors called neuromasts....
I know that hair cells, like the ones inside a human ear, are used as well.
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Answer:</h3>
The generation of local currents.
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Explanation:</h3>
An action potential at the axon hillock generates local currents that depolarize nearby sections of axon to threshold. This change in membrane potential causes voltage-gated Na+ channels to open in the adjacent axon segment. This generates/regenerates the action potential in the adjacent segment, causing the action potential to propagate away from the axon hillock.
