summary 3 cycle of life

WATER CYCLE
THE EARTH HAS A LIMITED AMOUNT OF WATER.
THAT KEEPS GOING AROUNG AND AROUND IN
WHAT WE CALL THE WATER CYCLE.
This cycle is made up of a few main parts:

• evaporation (and transpiration)
• condensation
• precipitation
• collection.

the carbon dioxide
In the atmosphere, carbon is attached to oxygen in a gas called  carbon dioxide (CO₂). With the help of the Sun, through the process of photosynthesis, carbon dioxide is pulled from the air to make plant food from carbon.
Through food chains, the carbon that is in plants moves to the animals that eat them. Animals that eat other animals get the carbon from their food too.

the nitroyen cycle
• All life requires nitrogen-compounds, e.g., proteins and nucleic acids.
• Air, which is 79% nitrogen gas (N₂), is the major reservoir of nitrogen.
• But most organisms cannot use nitrogen in this form.
• Plants must secure their nitrogen in "fixed" form, i.e., incorporated in compounds such as:
• nitrate ions (NO₃⁻)
• ammonia (NH₃)
• urea (NH₂)₂CO
• Animals secure their nitrogen (and all other) compounds from plants (or animals that have fed on plants).
• Four processes participate in the cycling of nitrogen through the biosphere:
  • nitrogen fixation
  • decay
  • nitrification
  • denitrification
  Microorganisms play major roles in all four of these.
• the end.