The Earth’s crust is divided into large sections like puzzle pieces called plates. The plates move due to uneven heating in the mantle which causes the molten rock to circulate. This circulation is called .

The nervous system interacts with the endocrine system by a. using hormones as connections b. sending nerve impulses directly to glands c. using neuroendocrine cells as connections d. sending neurotransmitters directly to neurons

20 the compound al(nh3)2 has atoms of nitrogen.

Adescription of a type of bio biotechnology (genetic engineering, cloning, or artificial section) one benefit or one risk for the individual (based on whether you are for or against it) one benefit or one risk for society (based on whether you are for or against it) one benefit or one risk for the environment (based on whether you are for or against it)