Below are the hypothetical between-host phylogenies of two different genes from the same virus strain. The products of both genes are localized on the surface of the virus particle
If you were charged with developing a vaccine against this virus, which gene would you target?
a. Gene A, as it does not appear to be under positive selection by the immune system.
b. Gene A, as it appears to be under positive selection by the immune system.
c. Gene B, as it does not appear to be under positive selection by the immune system.
d. Gene B, as it appears to be under positive selection by the immune system.
A
You might also like to view...
Cytotoxic T cells destroy target cells by
A. the CD95 pathway. B. the perforin pathway. C. direct killing mediated by activated oxygen species. D. both direct killing mediated by activated oxygen species and the perforin pathway. E. both the perforin pathway and the CD95 pathway.
Which of the following correctly describes the fate of the embryonic germ layers?
A. The endoderm forms the gut, the ectoderm forms the epidermis and parts of the nervous system, and the mesoderm forms muscles and most internal organs. B. The endoderm forms the gut, the ectoderm forms the reproductive tract and endocrine system, and the mesoderm forms muscles and most internal organs. C. The endoderm forms the inner part of all internal organs, the mesoderm forms the middle parts, and the ectoderm forms the outer coverings. D. The layers are sequential structures that all disappear during development, with the endoderm appearing first and then is replaced by the mesoderm, which in turn is supplanted by the ectoderm. E. The endoderm is an embryonic structure that disappears early, whereas the ectoderm persists as the skin and the mesoderm as the internal organs.
Which statement correctly describes infertility?
a. Infertility only occurs in females. b. Infertility is always caused by low sperm counts in males. c. Infertility is diagnosed when a couple is unable to become pregnant after 7 months. d. Female infertility is only caused by hormonal imbalances. e. Female infertility may be caused by environmental factors, such as rigorous physical exercise.
Refer to the accompanying figure. Which region of the skin insulates the body from outside temperature extremes?
a. 1
b. 10
c. 11
d. 14
e. 15