Answer:
The nitrogen cycle could not exist without nitrogen fixing microbes. These microorganisms are capable of transforming the atmospheric nitrogen in the form of fixed nitrogen. This form of nitrogen can be used by the plants. More than 90 per cent of the nitrogen are converted into usable form by the help of nitrogen fixing bacteria.There are basically two steps in nitrogen cycle. Nitrification and denitrification. The conversion of ammonia to nitrate is called nitrification and the conversion of nitrates into nitrogen is called Denitrification. The Rhizobium, Clostridium, some blue-green algae, Pseudomonas are some species of bacteria involved in Nitrogen Cycle.
Explanation:
The population ecologist is trying to determine the density of the oak
trees in a forest. It is a part of the job of a ecologist. By detecting
the density of the oak trees, an ecologist can easily determine whether
the density of the oak trees are decreasing or increasing with time and
what are the steps that need to be taken to keep the balance.