Which of the following best explains the importance of Earth’s crust to living organisms? a. The continental crust allowed the evolution of life on land. B. The crust provides raw materials necessary for life. C. The crust allowed the formation of fossil fuels. D. The rock cycle recycles sedimentary rocks formed from animal shells. Please select the best answer from the choices provided A B C D.

Choose the correct words to complete the sentences related to genetic screening. is a procedure that is used during pregnancy to detect genetic defects. is extracted from the uterus and used to identify genetic disorders?

The two tubes contain bromothymol blue. after 24 hours, what will the color of the water be in tube b? a. green (it won't change) b. yellow c. blue d. colorless (clear)

Which of the following is an advantage of using embryonic stem cells in medical research? a. the use of embryonic stem cells is much less expensive than the use of adult stem cells. o b. no living tissue is damaged when scientists use embryonic stem cells. o c. embryonic stem cells are able to differentiate into a wider range of cells than adult stem cells. d. there is no controversy surrounding the use of embryonic stem cells.