Describe two things that would happen in an ecosystem if there were no unicellular organisms.

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?

According to the cladogram, which organisms have roundworms as a common ancestor?

Which example describes a mutualistic relationship between organisms? young wasps prey on caterpillars. crabs eat the remains of dead fish. tapeworms feed on food in the intestines of cats ants protect a tree on which they feed.