Me solve 17a and b with explanations

Which property is used to identify the origin of an igneous rock? color density hardness crystal size

Ryan rears sheep for their wool. recently the quantity of wool that ryan gets has diminished. this is because the new sheep are not that wooly. ryan should add which nutrient to their feed so that the sheep becomes more wooly? a.cornb.ironc.cottonseedd. vitamin a

Twind is considered to be an abiotic factor because it.?