The conservation hawks and owls is important to mankind chiefly because these birds eat

The correct answer is C. many harmful rodents.

Hawks and owls are birds of prey, which means they eat other animals. They are important to mankind because they help to control the populations of harmful rodents, such as mice and rats. Rodents can damage crops, spread disease, and even bite people. Hawks and owls help to keep these populations in check, which benefits humans.

Option A is incorrect because hawks and owls do not typically eat other birds. Option B is incorrect because hawks and owls do not typically eat reptiles. Option D is incorrect because hawks and owls do not typically eat weed seeds.