Fixation
Nitrogen is converted from atmospheric nitrogen (N2) into usable forms, such as NO2-, in a process known as fixation. The majority of nitrogen is fixed by bacteria, most of which are symbiotic with plants. Recently fixed ammonia is then converted to biologically useful forms by specialized bacteria
Answer:
They release chemical messengers to communicate with cells they may or may not be in direct contact with.
Explanation:
Unicellular organisms such as bacteria or yeast, 'talk' to each other through the release of chemicals. In bacteria, this is known as quorum sensing which allows them to determine the surrounding bacterial population density. In yeast, one of the more popular pathways is known as the mating factor pathway, which allow the organisms to find mates. Whereas, in multicellular organisms (such as humans), this chemical release allows for cell-cell co-ordination which keeps the system functioning correctly.
Soil and air because it is needed for the development of living beings
There is no illustration attached, so it is impossible to answer this question. I apologise.
