Which atom is involved in giving your heart energy to beat?
carbon
gold
oxygen
iron

Consider this plant cell which organelle is labeled g

When a person is exercising the body needs to deliver increased amounts of oxygen to the muscles which component of blood ensures that the muscles will receive it

During the winter, this species of fox has white fur, but in the summer, it has brown fur. what environmental change may have lead to this fox's fur color? snow cover increase in sun's brightness volcanic eruption global warming