Sources of heat in the early earth included

a. Compression by gravity

b. The impact of colliding particles as they came together to form the earth

c. Decay of radioactive elements

d. All of the choices are correct

Which of the following protists gets nutrients mainly by absorbing molecules from other organisms through their cell walls and cell membranes? a. amoebas b. water molds c. ciliates d. slime molds

Which of the following is a consequence of urban heat islands? increased precipitation downwind of the city? increased precipitation upwind of the city? decreased winds within the city? increased winds within the city?

What is the main reason that attitudes are more often revealed in spoken rather than written language? a. in writing, we try to put the "best face" on what we write. b. we speak far more often than we write. c. in writing, we can more easily conceal our attitudes. d. in spoken language, we are often careless in our use of words.