What is the collective role of water vapor, carbon dioxide, ozone, and methane in the atmosphere?

a) they prevent the harmful ultraviolet radiation of the sun from reaching earth.
b) they are important components of the water cycle, which regulates earth's temperature.
c) they regulate earth's climate by trapping heat and holding it within earth's atmosphere.
d) they scatter almost a third of the sunlight that reaches the outer layers of the atmosphere back into space.

The correct answer is A) and C).

Water vapor, carbon dioxide, ozone, and methane are the essential greenhouse gases. They prevent the harmful ultraviolet radiation of the sun from reaching the earth. This is because they trap the heat energy and hold it within atmosphere. Due to this, they help in the regulation of the earth's climate.

Thus, the correct answer is-  A)  They prevent the harmful ultraviolet radiation of the Sun from reaching Earth.

C) They regulate Earth's climate by trapping heat and holding it within Earth's atmosphere.