Which of the following is true about cells?
a. cells have specialized components that perform different, specific functions.

b. cells have specialized components that all perform the same functions.

c. a cell's components are all identical and perform the same function.

d. a cell has a single component that performs all of the cell's different, specific functions.

the national environmental policy act (nepa) is a united states environmental law that promotes the enhancement of the environment and established the president's council on environmental quality (ceq). the law was enacted on january 1, 1970. to date, more than 100 nations around the world have enacted national environmental policies modeled after nepa.

answer:

convection currents in the magma drive plate tectonics. heat generated from the radioactive decay of elements deep in the interior of the earth creates magma (molten rock) in the aesthenosphere. the aesthenosphere (70 ~ 250 km) is part of the mantle, the middle sphere of the earth that extends to 2900 km.