The mechanisms of reproductive isolation prevent the reproduction of two individuals from different species. The prezygotic mechanisms disrupt the stages of reproduction before the forming of the zygote or prevent the mating at the start, and the postzygotic mechanisms affect the stages of reproduction after the forming of the zygote.
So, the first and the third example (the urchins and the grasshoppers) show the prezygotic mechanism, as the two individuals are not able to mate or form a zygote.
The second and the fourth example ( zonkey and the death of a zygote) show the working of the postzygotic mechanisms, as the zygote is formed, but it seems to be inviable, and the zonkeys are sterile, preventing the individual to reproduce.
"From the dog" is the prepositional phrase since it begins with the preposition "from" followed by the noun phrase "the dog" .
Answer:
The animals adapt to survive.
Explanation:
If a giraffe can't reach the food that another one can, that giraffe will die and the longer necked one wll survive. Adaptations over time cause evolution. The fittest will survive. (Darwinism)
