The blank era began and ended with mass extinctions

How do accessory pigments chlorophyll?

Which statement correctly identifies the scientific question and describes why the question is scientific? question 1 refers to the supernatural. question 2 reflects a moral or social value. question 3 refers to something that can be measured. question 4 reflects a question that can’t be observed.

A60-tooth gear is connected to a 72-tooth gear. if the smaller gear turns 12 times, how many turns does the larger gear make?