Video Transcript
Aerobic respiration requires
oxygen. How is this oxygen delivered to the
cells for respiration? (A) By red blood cells, (B) by
white blood cells, (C) by chemical messengers, (D) by the nervous system, or (E) by
active transport.
This question is asking about how
oxygen is carried around the body for cells to use. Oxygen is initially taken into the
body through the mouth and nose and then travels down through the trachea into the
lungs. At the ends of the bronchioles in
the lungs, there are little sacks called alveoli. These alveoli have a good blood
supply so that oxygen from the inhaled air can diffuse from the alveoli into the
blood. The oxygen then attaches to the
hemoglobin in red blood cells and is carried throughout the body via the
bloodstream.
So it is blood that carries and
delivers oxygen to cells in other parts of the body, or specifically the red blood
cells in the blood that do this job. Therefore, the correct answer is
(A). Oxygen is delivered to cells for
respiration by red blood cells.