Stem cells are injected into the retina to replace dead cells in the treatment of which disease?

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?

The model illustrates a process by which a substance is taken up by a cell

Which type of organism is missing from the food web seen in the illustration? primary consumers decomposers primary producers secondary consumers