Answer: Option D.
A region of DNA consisting of the promoter and operator sequences needed to regulate one or more structural genes.
Explanation:
An operon is a part of the the DNA that is found in bacteria or viruses which function in transcription and genetic regulation. Operon is under control of an operator, consist of promoter, regulator and structural genes. Operon is normally under the control of a single operator in which genes coding for protein are clustered along the DNA.
<span>The celiac trunk is the first major branch of the abdominal aorta. This branch works hard to bring blood that is rich in oxygen to major organs like the esophagus, spleen, stomach, liver as well as a some parts of both the pancreas and duodendum.</span>
