How does an owl's niche in our valley affect the ecosystem on a farm?

owls invade rodents that maintain ecosystem.

Explanation:

Farms have huge importance in term of food production and maintaining ecosystem (having all level of tropic levels). But, crops and vegetations are normally destructed by rodents. Thus, rodents are invaded by owls which helped to control crop damage and increase yield production that eventually maintain ecosystem of farms.

the answer is b.) hydrogen bonds between bases.