Imagine a simple food chain: grass -> grasshoppers -> mice -> snakesif snakes that eat mice are added to the ecosystem, would you expect the amount of grass to increase or decrease

Decrease

Explanation:

If the snake population is increased, it would prey on more and more mice and would cause a decline in the mice population. A decline in the mice population would cause an increase in the grasshopper population due to a lesser number of their predator grasshoppers. The increased grasshopper population would feed on more and more grass and would cause a decline in the amount of grass. Therefore, an increase in the number of top predator snake would adversely affect the primary producer "grass" of the given food chain.

true, i don't really know what you're asking but from the info you provided im guessing the answer is true.