The total amount of water on earth
a. is increasing.
b. is fairly constant.
c. is decreasing.
d. depends on the weather.

The correct answer is fairly constant.

The total amount of water on the earth remains fairly constant on the earth. The regulation of the mount of water on earth is maintained by the water cycle.

The water from the seas, ocean and other water bodies gets evaporated and gets stored in the clouds that comes down to the earth in the form of precipitation.

Through water cycle the amount of water on earth is fairly constant.

answer; //the above statement is (false);

answer: - b cells

explanation: -

so, the b cells mediate their action by identifying the antigens present on the surface of the pathogens and then producing antibodies in return to mediate its effect.