A population of hummingbird feeds exclusively on nectar from orchids. Two species of

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?

How many cells are our body made of ? ♡

Which of the following types of rock would most likely contain a fossil? slate granite lava rock limestone