Which of these organisms skeleton also acts as a skin
a. flower
b. elephant
c. tree
d. crab

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.

The breakdown of food is accomplished by enzymes. a. physical b. chemical c. mechanical d. none of the above

Hector is back from his morning run and is feeling light-headed because his energy is depleted which food item will provide him with a quick source of carbohydrates