Please help this is due tomorrow.

The eruption of a nearby volcano causes a prairie ecosystem to receive a lot less sunlight.which of these is the most likely effect on the ecosystem? a-an increase in biodiversity. b-an increase in immigration to the area. c-a decrease in available water. d-a decrease in plant growth.

Organisms that successfully adapt will leave to grownone of the above

What environmental cues and landmarks do the geese use to determine the timing and direction of their migration over the mountains? how do they find their way?