Final answer:
If the rat population decreases, it will most likely cause a decline in the snake population as they directly depend on the rats for food. Therefore, the correct answer is 'A) The snake population only'.
Step-by-step explanation:
Given the question, if the rat population, which serves as an intermediary in the food chain, decreases, it will impact the organisms that are dependent on them for their survival. In this case, this is particularly referring to the snake population. As per the principle of predator-prey dynamics, if the availability of prey (rats) decreases, then the population of predators (snakes) that rely on them for food will likely decrease as well. Therefore, the correct answer would be 'A) The snake population only' as they will experience a decline due to decreased food availability initiated by the reduction of the rat population.
Learn more about Predator-Prey Relationship