HIV selectively destroys CD4 cells and as a result, a person with AIDS is susceptible to life-threatening viral infections. Knowing this, you can conclude that __________.
A) regulatory T cells are killed by the virus
B) these viruses have T-dependent antigens
C) B cells do not recognize viral antigens
D) CD4 T cells need help from B cells to recognize viral antigens
Ans: B) these viruses have T-dependent antigens
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Describe what is meant by a "conformational disease" and give an example. Why do you think these diseases exhibit late age of onset?
What will be an ideal response?
The nerve impulse moves along the neuron because
A. a current flows along the cell. B. sodium ions flow from one end of the cell to the other. C. there is a high concentration of sodium ions at one end of the cell and a high concentration of potassium ions at the other end of the cell. D. depolarization of one portion of the nerve cell membrane changes the permeability of the adjacent portion of the membrane, allowing it to depolarize as well.
Species 1 more closely matched its mating time to the optimal mating time.
a. true b. false
Which of the following is a microbial product used to reduce crop damage?
A) Bt toxin B) saxitoxin C) ice-minus D) both Bt toxin and ice-minus E) both Bt toxin and saxitoxin