13. What is the main function of restriction enzymes in genetic engineering? (A) To join DNA fragment:together B. To cut DNA at specific sequences d. To copy DNA sequences d. To store genetic information

## Step 1<br />Restriction enzymes, also known as restriction endonucleases, are a type of enzyme that is used in genetic engineering. They are used to cut DNA at specific sequences, which is a crucial step in the process of genetic engineering.<br /><br />## Step 2<br />These enzymes are able to recognize specific sequences of DNA and cut the DNA at these specific locations. This allows scientists to isolate specific genes or DNA sequences for further study or manipulation.<br /><br />## Step 3<br />The other options provided, such as joining DNA fragments together, copying DNA sequences, or storing genetic information, are not the primary functions of restriction enzymes. These tasks are typically performed by other types of enzymes or processes in the cell.