Natural processes such as speciation and gradualism provide the genetic basis for
a.
evolution
c.
biogenesis
b.
spontaneous generation
d.
sexual reproduction

The answer is A. evolution

Explanation:

Taking into account that biological evolution is the set of changes in phenotypic and genetic characters of biological populations through generations, we can make a relationship and consider as a basis for this concept, gradualism, which is the belief according to which the Change occurs, or should occur, slowly in the form of gradual steps, and speciation, which is the process by which a population of a given species gives rise to another or other species.

showing a photograph would make this a hell of alot easier

step 1: nitrogen fixation- conversion of atmospheric no₂ into forms useful to plants by lightning, bacteria, and cyanobacteria.

step 2: nitrification-process of converting ammonia to nitrite or nitrate.

step 3: assimilation-plant roots absorb new form of nitrogen.

step 4: ammonification-conversion of organic nitrogen to ammonia by bacteria involved in decomposition.

step 5: denitrification-bacteria turns the decomposed matter back into n₂o, which is released into atmosphere; repeat cycle.