The correct answer that would best complete the given statement above would be CELL RESPIRATION and FOSSIL FUELS. Carbon dioxide enters the atmosphere by animal and human cell respiration and the burning of fossil fuels. Human activities such as BURNING FOSSIL FUELS and RESPIRATION cycle carbon through the carbon cycle. Hope this is the answer that you are looking for.
ATP fuels the primary active transport pump for Sodium and Potassium. The pump maintains a positive voltage on the exterior of the cell and negative on the interior.
A population will most likely deplete the resources of its environment if the population "increases".
Less than 5% of the water taken up by roots remains in the plant, that water is vital for plant structure and function. The water is important for driving biochemical processes, but also it creates turgor so that the plant can stand without having actual bones.