The Common Ancestor of the Protostomes Had a Coelom

question 24

Multiple Choice

The common ancestor of the protostomes had a coelom. What does this suggest?

• A) All lophotrochozoans have a coelom.
• B) There are no pseudocoelomates within the protostomes.
• C) There are no acoelomates within the protostomes.
• D) The body cavity evolved before the lophophore.

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Definitions:

Primary Drives

Basic physiological needs such as hunger, thirst, and sleep, which motivate behavior to ensure survival.

Stimuli

External factors or events that elicit a physiological or psychological response in an organism.

Drive-Reduction Principle

A theory suggesting that psychological needs create an aroused state that drives an organism to reduce that need by engaging in some behavior.

Acquired Drives

Learned motivations that are not innate but develop through experience, such as a drive for achievement.