The sa node acts as the pacemaker of the heart because these cells are

Which statements correspond to cellular respiration? co2 diffuses passively into the cell. co2 diffuses passively out of the cell. co2 must be pumped out of the cell. o2 diffuses passively when produced inside the cell. o2 diffuses passively when converted to co2. o2 is pumped in and forces co2 out.

The organelle pictured is found in cells of and is theorized to have once been an independent organism.

Select the word from the list that best fits the definition a system made of 25 satellites