The loss of ventral spines by modern freshwater sticklebacks is due to natural selection operating on the phenotypic effects of Pitx1 gene _____

A) duplication (gain in number)
B) elimination (loss)
C) mutation (change)
D) silencing (loss of expression)


D

Biology & Microbiology

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The Archaea generally lack which of the following that are normally found in Gram-negative bacteria?

A. a complex peptidoglycan network B. outer membrane C. lipopolysaccharide D. All of the choices are correct.

Biology & Microbiology

The most basic taxonomic group that can be defined as a collection of bacterial strains that share many common physiologic and genetic features is:

a. genus. b. species. c. class. d. kingdom.

Biology & Microbiology

Cenozoic

What will be an ideal response?

Biology & Microbiology

When bird populations migrate and mix with populations that do not migrate,  ________ will occur.

A. gene flow B. gene blending C. genetic drift D. mutation

Biology & Microbiology