Which statement describes many of the structures involved in the first line of defense of the immune system
sorry not geography lol

physical and chemical barriers

Explanation:

physical and chemical barriers try to prevent pathogens from getting inside the body

They have contact with the external environment.

(I took a test over this and got this question right)

the correct answer is blue and green.

a visible spectrum is electromagnetic spectrum color that can be seen by a normal human being by a single wavelength of light. the visible light spectrum is the range of wavelengths that make up visible light. the visible light spectrum passes through a prism enabling the rainbow reveals all the colors in the spectrum. these range from red, orange, yellow, green, blue and violet.

primary groups shape your individual development

explanation: