Ecosystem

Carbon cycle

100

Plants use CO2 in the process of __1____ to make __2___ and oxygen.

1. photosynthesis

2. Sugar

200

Animals use oxygen in the process of ______ and make more CO2.

Respiration

300

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

Decay

400

Equation of  photosynthesis:

6CO2+6H2O--->C6H12O6 + 6O2

Oxygen cycle

100

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

photosynthesis

200

Atmosphere oxygen in the form of ____ provides protection from harmful ultraviolet rays.

ozone

300

Oxygen is found everywhere on Earth, from Earth's ____ (rock) to the _____ where it is dissolved.

1. crust

2. Ocean

400

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

Respiration

Phosphorus cycle

100

Phosphorus in not found in the free state in Nature, but is contained mostly in _______ and  ________.

Rocks and minerals

200

It is an essential nutrient for life, as it makes up important chemicals such as _______.

DNA

300

In the phosphorus cycle, phosphorus moves between the soil and ____, which are eaten by animals.

plants

400

The animals use phosphorus, and then their _____ products help return the sulphur for the next generation of phosphorus in the soil.

waste

Nitrogen cycle

100

Nitrogen gas makes up____% of our atmosphere.

78%

200

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

Atmosphere

300

Higher organisms use nitrogen to make their _____

Proteins

400

What is the systems of cycles called...

Ecosystems