Cycles Worksheet

Plants use CO2 in the process of _______ to make _______ and _______.

Animals use oxygen in the process of _______ to make more CO2

The _______ is the main regulator of CO2 in the atmosphere because CO2 dissolves easily in it.

In the past, huge deposits of carbon were stored as dead plants and animals ________

Today these deposits are burned as _______, which include _______,_______,_______

More CO2 is released in the atmosphere today than in the past because of _____________.

Another natural source of CO2 is _______.

Too much CO2 in the atmosphere may be responsible for the ______________.

Plants release 430-470 billion tons of oxygen during the process of ________.

Atmospheric Oxygen in the form of ______ provides protection from harmful ultra violet rays.

Oxygen is found everywhere on Earth, from the Earths _______ to the _______ where it is dissolved

Oxygen is vital for _______ by animals, a process which produces CO2 and water

Oxygen is also necessary for the decomposition of _______ into other elements necessary for life

Phosphorus makes up important chemicals such as _____

Too much phosphorus in water leads to.....

Our atmosphere is ____% nitrogen gas

Animals and plants cannot directly use all the nitrogen found in our _________

Only special bacteria can directly use nitrogen in our atmosphere and fix it so other organisms can benefit. Called....

Higher organisms use nitrogen to make their....

Animal waste decay by the action of bacteria which create _______ and _______ products rich in nitrogen and you school for plants to use again

__________ bacteria in the soil can break down the ammonia into the gases form of nitrogen which is not available for use by plants or animals

And another part of the cycle animals eat______containing nitrogen which is again returned to the soil by animal ______ or decaying _______ and ______