Which of the following was observed by Erwin Chargaff?
A. Base composition of DNA does not vary from one species to another.
B. The DNA isolated from different tissues of the same species all have the same base composition.
C. Base composition changes as the organism ages.
D. In all species, the number of adenines equals the number of guanines.
E. In all species, A + T = G + C.
B
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You want to know whether cookies made with unbleached flour taste better than cookies made with bleached flour; which of the following has the strongest experimental design to test this question?
A. Make two batches of cookies, one with bleached flour and one with unbleached flour; one taster tries both types and ranks which type they like best. B. Make two batches of cookies, one with bleached flour and one with unbleached flour; twenty tasters try both types and rank which type they like best. C. Make two batches of cookies, one with bleached flour and one with unbleached flour; twenty tasters try both types without knowing which ones they are eating and rank which type they like best. D. Make two batches of cookies, both with bleached flour; one taster tries both types and ranks which type they like best.
Coconut milk was an extremely useful additive in plant tissue culture because, in addition to amino acids, it contains
A. auxins. B. gibberellins. C. cytokinins. D. ethylene. E. abscisic acid.
Under a system of positive control, transcription does not occur unless a regulator molecule directly stimulates RNA production
Indicate whether the statement is true or false
The characteristic lesion for tertiary syphilis is the presence of (gummas/necrosis/granulomas) in bones, in nervous tissue, or on the skin.
Fill in the blank(s) with the appropriate word(s).