The regulatory genes are not part of the lac operon.
Answer:
The correct answer is D. The surface of the skin can be mapped into distinct regions, each served by a single spinal nerve: these regions are called dermatomes.
Explanation:
A dermatome is the area of skin innervated by a single spinal nerve and its spinal ganglion. The cutaneous nerves are those that reach the skin, picking up the sensitivity of the skin. Each cutaneous nerve is distributed in a certain area of skin, called a dermatome.
A pair of posterior or sensory roots and a pair of anterior or motor roots arise from each cord segment, joining laterally at the level of the intervertebral foramen to form a mixed spinal nerve. Each of these innervates a strip of skin called a dermatome, so the body surface can be considered a true mosaic of these.
In the extremities the arrangement of dermatomes is more complicated because of the embryological rotation of the limbs as they grow from the trunk.
The purpose of the replication bubble is that it forms where replication is taking place (option A).
<h3>What is replication?</h3>
Replication is the process of producing replicas or duplicate of DNA or RNA molecules.
DNA replication is a very important process that occurs prior to cell division. During replication, the double stranded DNA is separated into two single strands.
Each copy called the leading and lagging strand becomes the template for the synthesis of new DNA strands.
However, a structure called replication bubble is a formed during the separation of two DNA strands by the helicase enzymes.
Therefore, the purpose of the replication bubble is that it forms where replication is taking place.
Learn more about replication at: brainly.com/question/16464230
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