Answer:A) Nitrogen
Explanation: nitrogen cycle ensures the movement of nutrients through the biosphere.it ensures that nitrogen is constantly reused and made available.
Nitrogen gas is available in the atmosphere but plants and animals cannot use it in that form.it must be converted to compounds such as ammonia or nitrate.
It is gotten from the atmosphere during rainfalls where it Is broken down and combines with oxygen to from nitrogen peroxide.
Nitrogen can also be fixated into ammonia by saprophytic bacteria.
Also when plants die their body tissues are broken down to form ammonia.ammonia can be oxidized into nitrates and nitrite which plants can use.
Nitrites can be released back into the atmosphere through denitrifying bacteria and the cycle continues.
A country like China would probably be in Stage 4 of the population with the low birth rate and low death rate due to their economic power have technology to prolong and save their citizen from diease and condoms
through the process of photosynthesis.
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