Define what makes up an ecosystem

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?

9. the history of life on earth is recorded in

When rutherford performed his metal foil experiment, he was surprised that most of the alpha particles