The most common source of DNA mutation is
a. cigarette smoke
b. UV light
c. errors in DNA replication
d. errors in protein synthesis
e. pesticides on the food we eat
C
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Which of the following is not true about anoxygenic photosynthesis?
A. Does not produce oxygen and often produces sulfur granules B. Does not produce oxygen C. Water is the usual source of electrons for photosynthesis D. Often produces sulfur granules
Forelimbs form at the junction of the neck and thoracic vertebrae, the position of which is controlled by HoxC-6 genes. Several kinds of vertebrates from different Classes are legless, including legless lizards, and amphibians known as caecilians. All descended from legged forms. On the basis of recent research in genetics what would you predict about the functioning of their HoxC-6 genes?
A. The site of expression of their HoxC-6 genes may have moved anteriorly until the level of expression has eliminated the neck region. B. The site of expression of their HoxC-6 genes would be the same as that of legged vertebrates but is simply turned off early in development. C. Their HoxC-6 gene has mutated and serves a different function than in legged vertebrates. D. The effect of the HoxC-6 gene is masked by another gene that is dominant to it. E. None of the other choices provided offer an adequate explanation and other reasons must be sought.
The diversification of Hawaiian honeycreepers as they colonized islands in the archipelago is an example of ________ speciation
a. sympatric b. allopatric c. parapatric d. allopolyploidy
Lymph moves throughout the lymph vessels due to
a. action of the heart. b. conscious actions. c. constriction of blood vessels. d. dilation of blood vessels. e. skeletal muscle and breathing movements.