Which of the following are pyrimidines found in the nucleic acid DNA?

A. adenine and guanine
B. thymine and cytosine
C. thymine and adenine
D. uracil and guanine
E. guanine and cytosine


Ans: B. thymine and cytosine

Biology & Microbiology

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Microevolution involves

A. an increase in the number of individuals in a population, but not a change in allele frequency. B. changes in a population's gene pool. C. changes in the ratio of males to females in a population. D. an increase in the number of individuals and a change in the ratio of males to females. E. an increase in migration, but not a change in allele frequency.

Biology & Microbiology

External cues such as increasing day length or warming after a cold snap stimulate gibberellin synthesis, which results

in bolting in plants such as cabbages.

a. True b. False

Biology & Microbiology

Which statement is true of deuterostomes?

a. The second opening into the embryo becomes the anus. b. They have two tissue layers. c. The second opening into the embryo becomes the mouth. d. The first opening into the embryo becomes the mouth. e. They are typically radially symmetrical.

Biology & Microbiology

Noncyclic electron transport needs a constant supply of electrons. These are obtained from:a

light. b. CO2. c. glucose. d. H2O. e. ATP.

Biology & Microbiology