Which is the only major phylum of animals that lack nerves?

A. cnidarians
B. sponges
C. platyhelminthes
D. nematodes
E. mollusks


Answer: B

Biology & Microbiology

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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.

Biology & Microbiology

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.

Biology & Microbiology

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

Biology & Microbiology

Which of the following requires treatment with both antibiotics and antitoxins?

A) diphtheria B) tuberculosis C) whooping cough D) scarlet fever E) psittacosis

Biology & Microbiology