Answer:
If the population of rabbits was altered then the food chain would be affected because if the population decreased then the animals that prey on rabbits wouldn't have as much food as they used to so the predators of the rabbits would decrease. If the population increased then the animals that prey on rabbits would increase. Overall, if rabbits had a change in population then the food chain would become effected, because if rabbits decrease then their predators decrease in population as well, the same goes for an increase in population.
(hope this helped!)