The Human Body Uses Three Lines of Defense to Protect

question 7

Multiple Choice

The human body uses three lines of defense to protect against pathogens. Match each of the following categories of defense to the type of cell or mechanism involved in the defense. Answers may be used more than once.
-acidic pH of skin

• A)physical or chemical barrier
• B)specific defense mechanism
• C)nonspecific defense mechanism

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Definitions:

Trichromatic Color Theory

A theory explaining human color vision based on the existence of three types of cones in the eye, each sensitive to red, green, or blue light.

Cones

Photoreceptor cells in the retina of the eye that function best in relatively bright light and enable the perception of colors.

Electromagnetic Spectrum

The range of all types of electromagnetic radiation, from radio waves to gamma rays, including visible light.

Nanometers

A unit of length in the metric system, equal to one billionth of a meter, commonly used to measure wavelengths of light and the scale of atoms and molecules.