The human genome has an estimated 25,000 genes on 23 chromosomes that can be affected by crossing-over and assorted into gametes. These gametes can then randomly combine into a diploid cell during fertilization. Given these numbers, about how many different combinations of chromosomes could be found in diploid offspring

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?

Animal bodies (and even plant bodies for that matter) are complex enough that life couldn't exist without enzymes. enzymes are usually large, complex biological catalysts that are expensive to make. enzymes speed up the rate of chemical reactions without being used up during the reaction (they can be reused many times). they are highly specific in the reactions they regulate. knowing what enzymes are and how they function, why does this explain why complex life forms could not exist if there were no enzymes.

What best describes the dropping height of a ball that bounces back up to a height of 45 cm