At which point on the phylogeny shown did the amnion first appear?
A. C
B. A
C. B
D. D
E. E
A
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Constitutive genes are those that have constant levels of expression
Indicate whether the statement is true or false
Ecologists use compartment models to
a. describe grazer food webs. b. describe detrital food webs. c. describe nutrient cycling d. describe species richness e. describe inputs of solar energy
Cloning a gene involves all of the following EXCEPT ________.
A. insertion of the gene into an appropriate vector B. isolating the fragment of DNA containing the desired gene C. introducing ligated DNA into E. coli cells D. expression of the vector and the gene in a cell-free environment
What is an endogenous rhythm?
a. The activity cycle generated by a biological clock that is not reset. b. the sleep pattern of a sleep-deprived person allowed to sleep without restrictions. c. a pattern of activity that varies unpredictably from one day to the next. d. the activity level of an animal that does not have a biological clock.