The Placenta

question 32

Multiple Choice

The placenta:

• A) a freely permeable layer of cells.
• B) a protective covering for the fetus.
• C) a sac in which the fetus develops.
• D) is a semipermeable membrane.
• E) a barrier that prevents the transfer of nutrients to the fetus.

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Definitions:

Dishabituation

A process in which a previously habituated response reoccurs, typically after the presentation of a novel stimulus.

Sensitization

An increased reaction to a stimulus following repeated exposures, leading to a heightened response.

Habituation

The process where an organism becomes less responsive to a stimulus after repeated exposure.

Behavioral Contrast

A phenomenon where the rate of response varies according to the reinforcement conditions of another behavior.