Which is the only major phylum of animals that lack nerves?
A. cnidarians
B. sponges
C. platyhelminthes
D. nematodes
E. mollusks
Answer: B
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Why would researchers want to have both genomic libraries and cDNA libraries from a particular
organism?
a. The genomic library is generally too big to be helpful; a cDNA library, being smaller, is much easier to study. b. A cDNA library will be the same in every cell; the genomic library tells researchers which genes are being expressed in individual cell types. c. The cDNA library helps us understand how retroviruses work; the genomic library does not. d. The cDNA library is a lot easier to clone than a genomic library. e. A genomic library will be the same in every cell; the cDNA library tells researchers which genes are being expressed in individual cell types.
Chromosomes that look alike and carry the same sequence of genes for the same traits, such as these shown from two parents, are
A. homologous chromosomes.
B. the X and Y chromosome.
C. found in females only.
D. found in males only.
E. all the autosomes.
Life-long nonsmokers live an average of how much longer than those who in their mid-twenties
smoked two packs of cigarettes a day? a. 6 months b. 1 to 2 years c. 3 to 5 years d. 7 to 9 years e. over 12 years
Which of the following requires treatment with both antibiotics and antitoxins?
A) diphtheria B) tuberculosis C) whooping cough D) scarlet fever E) psittacosis