Javier's heart beats 15 times in 20 seconds. What is his beats per minute?

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 these best describes what occurs during cytokinesis? a) the chromosomes are separated b) the cell begins to divide by replicating the chromosomes c) the cytoplasm is divided between the two new daughter cells d) the nucleus opens to allow the chromosomes to enter the cytoplasm

Tropical rain forests support more species per unit area than any other terrestrial ecosystem. what is one way rain forests are important to the health of the biosphere?