What does a marine fossil in a desert tell scientists? a. marine fossil could not be found in the desert b. the desert was always a desert c. the area was once under water d. marine life was once on land

Which of the following statements about archaea and bacteria is true? a. neither is single-celled. b. they both have nuclear membranes. c. neither reproduces by binary fission. d. they both lack a nuclear membrane.

20 the compound al(nh3)2 has atoms of nitrogen.

The diagram shows the development of the oocyte and the follicle during the menstrual cycle. identify at which stage in the cycle the hormone levels are at their highest and most active.