How do the geographic barriers affect the relatedness of species?

Scientists think that geographic isolation is a common way for the process of speciation to begin: rivers change course, mountains rise, continents drift, organisms migrate, and what was once a continuous population is divided into two or more smaller populations. This may or may not be sufficient to cause speciation.

Explanation:

c.muti cella's eukaryotic organisms began to diversify

a. decomposes use carbon from dead organisms as fuel for cellular respiration, returning carbon dioxide back into the atmosphere.