A molecule floats up from a rose petal what does that mean

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?

What is the relation ship between structure and function in an organism

How can antibodies "remember" a particular bacterial invader or "antigen" on that invader?