The probable cause for the relapsing nature of relapsing fever caused by Borrelia recurrentis is
A. periodic spore dormancy and activation.
B. organisms that survive and propagate after spirochete-induced fever
C. the sequential appearance of new antibiotic resistant variants.
D. successive appearance of antigenic variants.
E. periodic hormonal fluctuations in the host.
Ans: D. successive appearance of antigenic variants.
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When methanogens convert carbon dioxide to methane, it is a(n) ________ reaction.
A. aerobic B. oxidation C. ammonification D. reduction
The tissue located between the cortex and the vascular cylinder in a root is called the
a. endodermis. b. epidermis. c. meristem. d. parenchyma
Which of the following is an exception to the law of independent assortment?
a. monohybrid cross b. test cross c. gene linkage d. random mutation
Most known plant viruses are RNA viruses.
Answer the following statement true (T) or false (F)