Answer:
A. Bluebird population will decrease due to less food.
C. Grass population will decrease.
Explanation:
In this food chain, plants are the producer which are eaten by grasshoppers. These grasshoppers are the food of blue birds and blue birds are the source of energy for snakes. After spray of pesticides, the grasshoppers die due to application of pesticides. When grasshoppers decrease in population, the blue birds also reduced in numbers due to unavailability of food. This will also effect the snakes because blue birds decreases in population.