Answer:
The correct answer is inference.
Step-by-step explanation:
The inference refers to the conclusion based on the observation with the proofs. In the given case, the biologist witnessed a decline in the number of rabbits with time. He also witnesses that the reduction in the number of rabbits has taken place post the introduction of the coyote population.
He also witnesses that the population of coyote has upsurged. Thus, he suggested that the population of rabbits and coyote are in negative interaction, as an upsurge in the number of coyotes has led to a decline in the population of rabbit.