What would cause a decrease in the quality of circulating red blood cells

Which best explains how this maneuver unblock a person's airway?

The oxidizing agent our bodies use to obtain energy from food is oxygen (from the air). if you breathe 15 times a minute (at rest), taking in and exhaling 0.5 l of air with each breath, what volume of air do you breathe each day? air is 21% oxygen by volume. what volume of oxygen do you breathe each day?

In which case would a scientist choose to use a dissecting microscope rather than a compound microscope