At room temperature, an element is a

a. gas
b. liquid or gas
c. gas or solid
d. liquid, gas, or solid

The terrestrial planets are characterized by having a a.) silicate core b.) iron-rich silicate core c.) iron-rich metallic core d.) none of these

Which of the following types of pollution is most responsible for large numbers of deaths worldwide because of unsafe drinking water? (a) nutrient pollution (b) thermal pollution (c) pathogen pollution (d) sediment pollution

Which description shows competition in an environment? an organism that feeds on some food an organism that finds a place to sleep three organisms of the same species living in an area three organisms battling over limited resources