Using a molecular clock, scientists are able to estimate the amount of time that two species have been evolving independently.
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Answer
The main reason being the amount of food available.
Explanation:
Think of it this way:
If an animal is trying to find food but another species is looking for the same prey then its going to be increasingly difficult for the species to find prey and if there's not enough of the prey species then the population of the predator to go down.
That is why its considered a limiting factor.
Foxes Hawks and Owls will have to rely on other sources for food and be the most directly effected. You could make the argument that all the organisms will effected as some will see increased predation, while the plants will see a reduction in herbivores eating them.
