Which characteristics are common to all archaea and bacteria

a.

live in other organisms

b.

exhibit identical biochemical makeup

c.

have cell walls

d.

have a single circular chromosome

Which type of organism is missing from the food web seen in the illustration? primary consumers decomposers primary producers secondary consumers

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

Acell in the human nervous system whose primary function is to form myelin and the blood-brain barrier, respond to injury, remove debris, and enhance learning and memory is called a(n) cell.