Which one is not a cell of the immune system

white blood cells

t cells

b cells

red blood cells

i'd say that the moon rock is about 2.2 billion years old.

the wetland preservation movement began in the u.s. in earnest with the clean water act (cwa) of 1972. although not specifically written to protect wetlands, the cwa is comprised of a series of regulations designed to prevent pollutants from contaminating u.s. waters.