What is the primary reason that these animals are endangered? A. habitat loss
B. hunting
C. pollution
D. accidents
(Please help me)

Which of the following is a possible reason for sleep? a) growth b)digestive c)speed d)intelligence

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 big bang theory suggest that the universe is about - 300 million years old - 4.6 billion years old - 30 billion years old - 13 billion years old