<em>Mitochondrion (sing.) or mitochondria (plural)</em>
<h3><u>Explanation;</u></h3>
<em><u>Cellular respiration</u></em> is the process that generates most energy in the <em><u>form of ATP that is used by the cells to drive cellular processes</u></em> such as transport.
Most <em><u>energy is produced during cellular respiration in the mitochondria, </u></em>a process that involves breakdown of simple sugars to produce energy in the form of ATP, which is the usable form by the cell.
In the <em><u>mitochondria cellular respiration</u></em> occurs in three phases, <em><u>glycolysis, Kreb's cycle and the Electron transport chain</u></em>, which gives the most number of ATP molecules.