A substance that enters Earth's cycles and does harm to living things is

A. a pollutant.

B. freshwater.

C. hydrogen.

D. oxygen.

Three things are necessary for humans to keep their balance while walking on two legs.

What does nonmetal mean in science?

If a person is severely dehydrated, their extracellular fluids will become hypertonic to the intracellular fluid. what do you predict will happen to the person's cells

Explain why chances of nose bleeding increase with altitude in humans

What are 5 factors that can lead to evolution

A 14 month old child returns from surgery for an undescended testicle. when planning for the child's discharge, the nurse should remind the parents to observe their child for

How and why does soil and water heat and cool differently and how that affects the air above it

What is the adaptive (natural selection) benefit of the diving response in aquatic and marine mammals? do you think it has an adaptive purpose in humans of is it just a remnant of our evolutionary past?

What happens to the density of the Earth's Layers as you move towards the core of the earth

In humans, what is the results when a valve is leaking blood backward in the heart