What causes cancer cells to develop?

The answer is; cancer occurs due to unregulated cell division

This causes them to proliferate causing a mass of cells and affect neighboring tissues. The cells are usually undifferentiated and therefore do not function properly as tissue. This unregulated division is due to malfunction of the tumor suppressor gene that is significant in cell cycle regulation and apoptosis.

explanation:

b,bacteria convert nitrates

into nitrogen gas.

d,plants and animals take in

and use nitrogen compounds.

e,bacteria break down waste    

products and return nitrogen  

to the soil.

a,bacteria convert atmospheric

nitrogen to ammonia.

c,bacteria convert ammonia

to nitrites and nitrates.

a. the production of carbon dioxide through the process of photosynthesis