Every mature mhc-restricted b cell expresses either cd4 + or cd8 + co-receptors

a. True

b. False

How many times greater is 50 than 34?

Why do a chicken embryo and a cow embryo look very similar even though the adults do not?

One drawback of dams is that they can flood land upstream from the dam and reduce water flow downstream from the dam. A. true B. False

What is the purpose of a hypothesis? A.) it specifies the procedure for a scientific experiment. B.) it is a prediction of whether an experiment will give useful results. C.) it tells other scientists what kind of research they should be doing. D.

In mice, a short-tailed mutant was discovered. When it was crossed to a normal long-tailed mouse, 4 offspring were short-tailed and 3 were long-tailed. Two short-tailed mice from the F1 generation were selected and crossed.

What can cause changes in DNA sequences? A. mutations B. genetic drift C. gene flow D. proteins

What is the definition of chemical energy

Define and give three examples of a population

Harmless bacteria are what type of bacteria? Milady chapter 5

Which kind of action is a cause of air pollution? A. Poisons are released into a major river. B. Gasoline is burned by a car engine. C. Trash is dropped in a national wildlife preserve. D. Tuna are fished to extinction.