rain that contains dissolved nitric oxides or sulfur dioxide
acid rain
the mixture of gases surrounding the Earth
atmosphere
special tubes that carry the blood
blood vessels
the organ that controls all body functions
brain
the way we take air into our bodies and let it out of our bodies
breathing
the system formed by the heart, blood vessels and blood
circulatory system
to keep safe, to protect from extinction
conserve
a living thing (usually an animal) that eats another plant or animal
consumer
removal of trees by humans
deforestation
regions with very little rainfall
desert
a way to remove wastes from the blood with a machine if the kidneys do not work properly
dialysis
the process of breaking down food into very tiny particles
digestion
our natural surroundings
environment
the process of removing of waste products from the body
excretion
a way to describe the feeding relationship between plants and animals
food chain
the gradual increase in temperatures throughout the world
global warming
