why is air pressure greater at the earths surface?\na pressure is actually lesser at the earths surface.\nb…

why is air pressure greater at the earths surface?\na pressure is actually lesser at the earths surface.\nb gravity pulls more molecules toward the earths surface.\nc only smaller molecules are found at the surface, which increases pressure.\nd molecules are smaller and less abundant there.

why is air pressure greater at the earths surface?\na pressure is actually lesser at the earths surface.\nb gravity pulls more molecules toward the earths surface.\nc only smaller molecules are found at the surface, which increases pressure.\nd molecules are smaller and less abundant there.

Answer

Brief Explanations:

Air pressure is due to the weight of air molecules. Gravity pulls more air - molecules towards the Earth's surface, increasing the density and thus the pressure. Option A is incorrect as air pressure is greater at the surface. Option C is wrong because there is no such selectivity of only smaller molecules at the surface. Option D is incorrect as molecules are more abundant at the surface.

Answer:

B. Gravity pulls more molecules toward the Earth's surface.