The proportion of the air we breathe accounted for by oxygen is approximately

A. 50%.
B. 21%.
C. 5%.
D. 1%.
E. 78%.


Answer: B

Biology & Microbiology

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According to the chromosome theory of inheritance, ____

a. genes on chromosomes always assort independently b. paternal chromosomes determine the offspring’s phenotype c. maternal chromosomes determine the offspring’s phenotype d. genes and their alleles are carried on chromosomes e. genes are carried on chromosomes and alleles are the product of gene expression

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Analysis of many Drosophila maternal effect genes reveals that many are involved in:

a. female morphogenesis. b. programmed cell death. c. forming specific segments in the embryo. d. nonspecific differentiation. e. determining the polarity of the embryo.

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Which cells are important elements that comprise cell-mediated immunity?

A) B cells B) cytotoxic T cells C) plasma cells D) complement proteins

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The relationship between DNA and histones is most like

A) an egg yolk inside of an egg. B) a spoon cradling some peas. C) thread wrapped around a spool. D) the candy shell surrounding the chocolate in a piece of M&M candy.

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