What is keratin? what role does it play in the organs of the integumentary system

Is it considered muscle s ennervation if sympathetic fibers innervate the vessels within the muscle?

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?

Match the pollutants. 1. a chlorofluorocarbon smoke 2. a biodegradable organophosphate insecticide freon 3. particle pollution paint 4. hazardous waste monoxide 5. carbon is completely burned malathion 6. carbon is incompletely burned dioxide