Answer:
Option 1 and 2 are correct
Step-by-step explanation:
In a given ecosystem rabbits serve as prey for several predators. The growth of predator population is depended on the population of rabbits. The higher the population of prey, the higher is the population of predator.
Thus, if the population of rabbit is decreasing, then the population of predator such as hawks will decrease.
Since the rabbits eat grasses and shrubs, thus in their absence the productivity of grasses and shrubs will also increase.
Option 1 and 2 are correct