Which statement best describes cancer cells?
a. they grow as a single layer of cells.
b. they cease to reproduce after 20–50 mitotic divisions.
c. they reproduce only when needed to replace missing cells.
d. they are not regulated by contact inhibition.

Tlymphocytes mature in the? a. thyroid gland. b. bone marrow. c. spleen. d. thymus.

Which of the following statements about c4 carbon fixation is not true? a c4 carbon fixation is an adaptation for plants exposed to high light intensityb. c4 carbon fixation occurs in more plants than c3 carbon fixation.c c4 carbon fixation is more common in areas of high temperatures than c3 carbon fixation.d. c4 carbon fixation occurs in the inner cells of a leaf rather than the entire leaf.

What should be the strand of complementary dna produced by the strand of dna shown below cgt ata