Which describes a promoter?
A .the first part of an operon that regulates where, when, and to what level a gene is expressed
B. the part of an operon that, if attached by a repressor protein, suppresses the expression of a gene
C .a cluster of genes that are expressed or repressed as a group
D .an enzyme that helps DNA unzip prior to transcription

What is the relation ship between structure and function in an organism

Molecular models of two different substances are shown below. in the molecule on the left, the oxygen atom pulls on electrons more strongly than the hydrogen atoms. in the molecule on the right, the two oxygen atoms pull on the shared electrons with the same strength. water molecule, h, o oxygen molecule, oz when the two substances are put in the same container, they do not attract each other. why does this happen? a. they both contain oxygen. b. one is polar and one is nonpolar. c . they are both polar. d. they contain different elements.

Which of the following describes a boom period? a. as one population increases, another population decreases. b. as one population increases, the other population also increases. c. as one population decreases, another population increases. d. as one population decreases, another population also decreases