The first compound light microscopes were constructed by the end of the sixteenth century. What is a compound microscope?
A) they have two different light sources
B) it has a moveable stage
C) it has two lenses
D) its lens is double the size of the original microscope
E) the lens has two different colors
Ans: C) it has two lenses
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What type of regulatory transcription factor binds DNA and increases the transcription of a gene?
A. a repressor exerting negative control B. a repressor exerting positive control C. an activator exerting negative control D. an activator exerting positive control E. a combination of both a repressor and activator exerting negative control
Exclusive male parental care is much more prevalent in fish than in mammals because:
a. both male and female fish lactate. b. fish do not have the option of raising young in a defended nest site or den. c. fish are less intelligent and so do not develop pair bonds. d. most fish reproduce by external fertilization while most mammals do not. e. fish are less likely to live in habitats with high-quality resources.
Leukocyte esterase, an enzyme found in an active urinary system infection, is produced by
a) T lymphocytes. b) B lymphocytes. c) neutrophils. d) monocytes.
Shown below is a hypothetical DNA sequence from a virus. Also shown is the sequence of the mRNA that is synthesized from this DNA.DNA sequence:5'-AGCACCTGCCGAATGGGCCAAATCCTGCCGAATAAA-3'3'-TCGTGGACGGCTTACCCGGTTTAGGACGGCTTATTT -5'mRNA sequence (G* = G cap):5'-G*AGCACCUGCCGCCUGCCGAAUAAAAAAA....-3' The RNA was most likely transcribed by
A. RNA polymerase II. B. RNA polymerase III. C. RNA polymerase holoenzyme. D. RNA polymerase I.