The answer i'm need my class is in 1 hour

Which best explains how a heat pump can heat a room? cold air from the house is moved through pipes, where it absorbs thermal energy. warm air from outside is pushed into the house to replace the cold air. combustion warms the air when chemical energy is transferred to thermal energy. fuel is used to move a piston, which pushes warm air into the house.

Which of the following is the earliest era of earth's geologic time scale? cenozoic mesozoic precambrian paleozoic

Why are human population trends difficult to predict?