Cancer is usually due to:
A. exposure to chemicals or radiation.
B. mutations in stem cells.
C. a series of mutations that occur throughout
an affected tissue or organ.
D. a series of mutations that occur in a single
lineage of somatic cells.
E. a series of mutations that occur in multiple
lineages of germ cells.
D
You might also like to view...
The hormone oxytocin stimulates ____
a. meiosis of oogonia b. ovulation c. implantation of the embryo d. development of the fetal heart e. contraction of uterine muscles during childbirth
Two groups of your colleagues are arguing over the amount of energy required for a beaker full of Substance X to complete an endergonic reaction. The first group insists that only the activation energy for a single reaction is necessary, which will release at least enough energy to start a second and third reaction, until all the reactants are consumed. The second group strongly disagrees, insisting that the energy required is equal to the activation energy of a single set of reactants, multiplied by the number of reactant sets in that volume of Substance X. Which group is correct?
a. Group 1 is correct, if and only if the energy released by each set of reactants is sufficient to activate a secondary reaction, after accounting for entropy. b. Group 2 is correct; the amount of energy required must equal the activation energy of all of the reactants in the beaker of Substance X. c. Group 2 is half right; endergonic reactions absorb energy, so free energy, activation energy, and entropy losses for all reactants must be included. d. Neither group is correct; endergonic reactions occur spontaneously, and the reaction has likely been completed unnoticed during this argument.
If water is abundant, a plant's guard cells will and the stomata will .
A. collapse; open B. collapse; close C. swell; close D. None of the answer choices is correct. E. swell; open
Members of the genus Staphylococcus are normally associated with ________.
A. mucous membranes B. skin glands C. skin D. All of the choices are correct.