how much there is of something
amount/supply
what a person or animal does
behavior
to become smaller in number, amount or size
decrease
means to grow in size or in number
increase
the amount you have of something
supply/amount
when things are in _____, they are even
balance
to make a person or thing do what you want
control
to act together (dancing, speaking...)
interact
when things happen you usually ____ to it
react
when something is ____ it is hard to find or get
scarce
a long time of dry weather
drought
a group of animals and plants, the place they live in, and how they act together
ecosystem
a series of animals and plants in which each one feeds on the one below it
food chain
how high or low something is
level
a large, natural stream of water
river
a contest or struggle between two or more people or animals
competition
