Which of these is a possible disadvantage of biotechnology?
a. it could produce hardier crops.
b. it could be used to endangered species.
c. it could be used to develop medicines.
d. it could reduce genetic variation in crops.

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.