Which of the following was produced in experiments on primitive Earth conditions conducted by Miller-Urey and others?
A. methane and oxygen
B. ammonia and water
C. amino acids
D. ammonia and hydrogen sulfide
E. CO2 and H2O
Answer: C
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A transposable element composed of an antibiotic resistance gene, a recombinase gene, and inverted repeats is identified in a bacterial genome. This element can be any of the following except
A. an integrated conjugative element. B. a composite transposon. C. an insertion sequence. D. a unit transposon.
The fluorochrome stain that can be used to detect mycobacteria is:
a. calcofluor white. b. acridine orange. c. auramine. d. immunofluorescence.
The relationship between nectar-producing flowers and nectar-feeding birds is a mutually beneficial interaction
Indicate whether the statement is true or false
Which of the following statements about cancer defense is false?
a. Natural killer and cytotoxic T cells destroy cancer cells. b. Cancer antigens stimulate a strong immune response. c. Monoclonal antibodies can deliver toxic drugs to cancer cells. d. T cells produce interleukins, which defend against cancer. e. Macrophages produce tumor necrosis factor, which inhibits tumor growth.