Which of the following could be true of two different species that have a competitive relationship in the same ecosystem?
a.) one species preys on the other.
b.) the relationship is mutually beneficial.
c.) they share the same niche.
d.) one species benefits, while the other is neither nor harmed.

C (they share the same niche)

Explanation:

Competition is a relationship between organisms resulting in a contest when both are trying to use the same resources related to their growth, reproduction and survivability. It is as a result of limited resources. Competition occurs in virtually all ecosystems in nature. This relationship develops when more than one organism in an environment has the same need for resources (niche) as another, to survive.

Each organism has a specific place in the ecosystem called NICHE. A species' niche is basically its ecological role or the function to which it is especially suited, which is defined by the set of conditions, resources and interactions it needs or can use.

The competitive exclusion principle says that two species can't coexist if they occupy exactly the same niche (competing for identical resources) or to put it in another way, two species in an ecosystem are bound to compete when they share the same niche (need for resources).

you are certainly talking about this picture:

a: is the label of the white square, it is showing the  replication fork, formed by helicase (d) ==> so it is the site of dna separation and replication 

b: is a new dna brand that is following directly the replication fork, so it is continuous ==> built continuously from 5' to 3

c: dna polymerase cannot replicate dna on its own, it needs the of their proteins, and one of them plays the role of a clamp which fixes  the dna with the dna template and increases  the processivity of the enzyme. ==>   stops polymerase from falling off the  template.

d: is the enzyme responsible for forming the replication fork (helicase) ==> unwinds and separates dna into two strands

e: is the delayed strand, it is built  in the opposite sense of the helicase, so dna will be built in fragments ==> built  fragments from 5' to 3 joins

and finally f: is the enzyme that builds  the new dna strand (dna polymerase) ==>   adds nucleotides to make a new dna helix.

credit: gradman555p98x9p

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1) gene flow

- it is described as the transfer of genes from one population to another population so that frequency of gene is increased.

-a zebra migrates to join a different herd of zebras.

2) natural selection

- a mechanism of evolutionary change in which individuals with advantageous traits survive and reproduce whereas the others ( those that can not adapt) eliminate from the population.

-competition for sunlight leads to taller trees.

3) mutation

- permanent change in the nucleotide sequence of dna ( genetic material) that could have harmful or useful consequences.

-the dna of a snake changes to make its venom stronger.

4) genetic drift - it is a random phenomenon ( that occurs by chance such as fire) that results in change in the gene frequency in a small population.    

-a grassfire randomly sweeps through a population of buffalo and kills most of the animals.

explanation: