The portion of the tooth that is used for mastication and is visible in the oral cavity is the

a. root.

b. cervix.

c. gingiva.

d. crown.

How do solar energy and the greenhouse effect impact Earth's global climate system?

Arteries contain blood that is ... a. high in oxygen b. low in oxygen c. both high and low

Explain why living organisms need nutrients

Leah found the eggs of an insect on a blade of grass. She brought the blade of grass home and made a container for it to keep the young insects safe when they hatch. Explain how she can tell what kind of insect eggs she found.

The properties and interaction of magnets are referred to as

Which of the following is NOT a renewable form of energy? A. Biomass B. Solar C. Coal D. Geothermal

How are changes in populations related to the availability of an ecosystem's resources?

As ocean depth increases, pressure increases, and temperature decreases. True False

What conditions are needed for an accurate radiometric date to be obtained from a mineral sample?

What covers the ends of bones in adults? A blood B cartilage C marrow D ligaments