The Number of U

question 26

Multiple Choice

The number of U.S. workers in unions today is:

• A) roughly equivalent to what it was in the 1950s.
• B) about 13%of all wage and salary workers.
• C) just under 15 million Americans.
• D) not something we can estimate due to the lack of information on all people in the labor market.

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Definitions:

Glial Cells

Cells within the central and peripheral nervous system, not of neuronal origin, that offer both support and protection to neurons.

Tropic Molecules

Substances that guide the growth or movement of developing cells or parts of an organism in response to certain stimuli.

Growth Cones

Dynamic, actin-supported extensions of a developing or regenerating neurite seeking synaptic partners by sensing their environment.

Neurotrophic Factors

Proteins that support the growth, survival, and differentiation of neurons and synaptic connections in the nervous system.