The correct answer would be: dependence on nonrenewable resources.
A nonrenewable resources are resources that cannot be readily replaced by natural means, such as fossil fuels (oil, natural gas). The use of these resources is not sustainable because their formation takes billions of years. The whole world is dependent on these non-renewable sources but they are becoming more scarce daily.
Diffusion , the movement of gas molecules .
Cell has cell membrane<span> (also known as the </span>plasma membrane<span> or </span>cytoplasmic membrane<span>) it is a </span>biological membrane<span> that separates the </span>interior<span> of all </span>cells<span> from the </span>outside environment.<span> The cell membrane is </span>selectively permeable<span> to </span>ions<span> and </span>organic molecules<span>and </span>controls the movement of substances<span> in and out of cells.</span><span>The basic function of the cell membrane is to protect the cell from its surroundings.</span>
