When You Stand at Rest on a Floor, the Number

question 64

Multiple Choice

When you stand at rest on a floor, the number of vertical forces acting on you is

• A)zero.
• B)one.
• C)two.
• D)three.
• E)four.

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Definitions:

Parabronchi

The small, air-filled tubes in the lungs of birds through which air flows for highly efficient gas exchange.

Countercurrent Exchange

A mechanism occurring in nature and designed systems wherein two flowing bodies of water, air, or other substances move in opposite directions of each other to maximize the transfer rate of heat or matter.

Concurrent Exchange

A process in which two substances, such as blood and air in the lungs, flow in opposite directions to maximize the transfer of gases or other molecules.

Tracheal Tubes

A network of air tubes in insects that branch throughout the body for gas exchange.