Answer:
D. Multiple antibiotic resistance genes.
Explanation:
A plasmid with multiple antibiotic resistance genes is important during cloning as it helps in selectivity of the specific clones during transformation of bacteria.
Vertebrates developed about 550 million years ago. The oldest vertebrate fossils are those of FISH with no jaws. These e<span>arly jawless fish did not have paired fins and their bodies were covered with heavy, bony scaled, but their skeletons were made of cartilage. For the next 50 million years, they were the only vertebrates.</span>
