Cells divide for many reasons. For example, when you skin your knee, cells divide to replace old, dead, or damaged cells. Cells also divide so living things can grow. ... Organisms grow because cells are dividing to produce more and more cells.
Cellular respiration is the process by which living organisms convert their chemical energy from nutrients into ATP. Cellular respiration is one of the major ways by which living organisms release chemical energy to drive chemical activities. Cellular respiration cause loss in dry weight. This is because, during cellular respiration there is release of energy from the living organism, carbon dioxide and oxygen are also exchanged. The energy that has to be spent during respiration is responsible for the loss in mass in living organisms.