Which combination is correct for making a recombinant vector?

Correct answer: Vector plus insert DNA plus ligase

The direct answer is A: vector plus insert DNA plus ligase. A vector is a DNA carrier, and the insert is the desired foreign DNA fragment. First, the vector and insert are cut or prepared with compatible ends. Next, the insert is placed into the vector, and DNA ligase seals the matching ends by forming phosphodiester bonds. The resulting joined DNA is a recombinant vector. A is correct because it includes both essential DNA parts and the joining enzyme. B, water plus salt plus fat, is a mixture of ordinary substances and cannot make a recombinant DNA molecule. C, protein plus chlorophyll plus soil, combines unrelated biological materials and lacks a DNA vector and insert. D, starch plus oil plus light, also has no DNA components or ligase. The exact laboratory mixture can include other reagents, but among these choices A gives the relevant combination. Memory cue: vector is the vehicle, insert is the passenger, and ligase seals them together.