Solution

a. Speciation refers to the emergence of new plant and animal species as a result of evolution. b. Because each species thrives in a distinct geographical area, it has a unique habitat, food source, reproductive capabilities, and life cycle. C. Physical isolation occurs when a population is split into two or more groups by geographical barriers such as rivers, exposing organisms to diverse geographic environments, resulting in speciation. d. Reproductive isolation is caused by genetic variety in organisms, which leads to speciation through time. As a result, geographical and reproductive isolation of species leads to speciation over time.