What are the building blocks of nuceic acids

Which of the following is a possible reason for sleep? a) growth b)digestive c)speed d)intelligence

Astudent reads the following text in a science book: scientific evidence tells us that the cause of earths four seasons is the tilt of earth as it revolves around the sound the student is instructed to illustrate this information in a science book. how will the student illustrate winter in the northern hemisphere? a.earths northern hemisphere will tilt away from the sun. b. earths northern hemisphere will tilt toward the sun. c.earths orbit will be farther away than from the sun d. earths southern hemisphere will tilt away from the sun.

Which are characteristics of flukes? check all that apply. a they are free living. b they are a type of flatworm. c they reproduce sexually. d they have eyespots. e they are segmented.