7th grade science need help

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

Which of these serves as a reference for comparison during a scientific investigation? a)outcome variable (dependent variable) b) test variable (independent variable) c)control group d)hypothesis

African penguins, which inhabit the coasts of southern africa, were classified as an endangered species in 2010. two significant threats to their survival are ecosystem damage from oil spills and overfishing by humans. overfishing depletes the food supply of african penguins. the best method to reduce the threat of overfishing would be to . the risk of oil spills could be reduced by increasing the use of , which should oil consumption. if an oil spill does occur, could be used to remove the oil so the ecosystem may more quickly recover.