Permian extinction : how did the earth get to these conditions ? form and effect

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

When you run, you begin to breathe heavier and faster. your heart beats more quickly, bringing more oxygen to your cells. which organ systems are working together here?

Which of the following was not a major animal on land during the carboniferous period? amphibians insects both a and b none of the above