Answer:
1. True
Biotic factors can have effect on abiotic factors like water by the way they use it and how much they drink. If biotic factors drink too much water in a rivver then it could end up with limited amount of water for the ecosystem.
2. False
On average, about 50 percent of energy available within one trophic level is transferred to the next trophic level.
3. True
Extirpation is extinction of a species in a given area.