Why are tiny bacteria so important in these cycles?

Bacteria are essential in cycling the nutrients back into the soil for plants to use, and cycling nitrogen back into the atmosphere. Nitrogen is found everywhere in the world, including animal waste, the atmosphere, and decaying matter.

haploid cells;

the correct answer is 4) heat and pressure

metamorphic rocks arise from transformation of existing rocks types, in a process called metamorphism. during metamorphism the original rock(prolith) change into metamorphic rock by heating (150-200c) and pressure of more than 1000 bar. the original rock can be sedimentary, igneous, or existing metamorphic rock.