Which of these is a regulatory gene?
a. structure of the lac operon. it contains definite structures labeled from a to e. letter a marks a gen before structural genes.
b. marks a part of the operon that consists of lac z, lac y, and lac a genes.
c. indicates a structure that moves along the operon.
d. marks lac l. this part is located before the others in the sequence.
e. indicates a molecule that can bind to structure a.

B. Marks a part of the operon that contains lac Z, lac Y and lac A genes

Explanation: Regulatory genes are which are involved in the controlling of the expression of other genes. So, whether a gene will be expressed is dependent on the presence or absence of these regulatory genes.

the relative standard reduction potential of the half-cell in which reduction occurs; more positive than the other half-cell. reduction is a chemical process in which electrons are added to an atom or an ion; it always occurs accompanied by oxidation of the reducing agent.

kelp are large brown algae that live in cool, relatively shallow waters close to the shore. they grow in dense groupings much like a forest on land. these underwater towers of kelp provide food and shelter for thousands of fish, invertebrates, and marine mammal species.

e) all of the above