When Did the Most Severe Mass Extinction on Earth Occur

question 19

Multiple Choice

When did the most severe mass extinction on Earth occur?

• A)at the end of the Cambrian
• B)at the end of the Devonian
• C)at the end of the Jurassic
• D)at the end of the Permian

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Definitions:

Myelinization

The process of forming a myelin sheath around the axons of neurons, which increases the speed at which electrical impulses propagate along the nerve cells.

Synapse

The junction between two neurons or a neuron and a muscle where information is transmitted from one to the other.

Dendrites

Branchlike parts of a neuron that are specialized to receive information from other neurons or receptor sites.

Axon

A part of a nerve cell that carries electrical impulses away from the neuron's cell body.