What Is the Myelin Sheath

question 46

Multiple Choice

What is the myelin sheath?

• A) The basic unit of the nervous system.
• B) The innermost layer of the protective covering of the CNS.
• C) A fatty insulation covering of the axon.
• D) A long, threadlike extension of the nerve cell.

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Definitions:

Carrier

A person who carries and transmits characteristics but does not exhibit them.

Recessive Gene

A genetic trait that is expressed only when two copies of the gene are present, often overshadowed by a dominant counterpart.

Sickle Cell

A genetic blood disorder that results in red blood cells assuming a sickle shape, leading to problems such as pain, infections, and anemia.

Recessive Gene

A type of gene that is not expressed in the phenotype unless two copies of the gene (one from each parent) are present.