The Wings of Bats and Birds and the Flippers of Porpoises

question 38

Multiple Choice

The wings of bats and birds and the flippers of porpoises are

• A) analogous structures.
• B) totally unrelated.
• C) functionally different.
• D) homologous structures.
• E) similar by chance.

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Definitions:

Synovial Membranes

Membranes lining the joint cavities, producing synovial fluid to lubricate and nourish the joints.

Negative Pleural Pressure

The subatmospheric pressure in the pleural cavity that helps keep the lungs inflated.

Surfactant

A substance that tends to reduce the surface tension of a liquid in which it is dissolved, significant in the lungs for preventing alveolar collapse.

Intra-Alveolar Pressure

The pressure within the alveoli of the lungs, critical in the mechanics of breathing and the exchange of gases.