Final answer:
Vectors must indeed have at least one restriction enzyme recognition site to facilitate the insertion of foreign DNA and the creation of recombinant DNA molecules, confirming the statement as true.
Step-by-step explanation:
True, vectors must have at least one restriction enzyme recognition site for the purpose of cloning. Vectors, such as plasmids, are specifically engineered to include these sites to allow the insertion of foreign DNA. This site is typically located within genes coding for selective markers so that the insertion of foreign DNA inactivates the gene, enabling easy identification of successful recombinant DNA. The cleavage by restriction enzymes at these sites creates sticky ends or blunt ends, which can be joined with foreign DNA that has been cut by the same enzyme, allowing for the formation of recombinant DNA molecules. The enzyme DNA ligase then glues these annealed fragments together, completing the cloning process.