Which option gives the correct sequence involving vector and restriction enzyme?

Correct answer: Restriction enzyme cuts vector then insert is ligated

The direct answer is option A: the restriction enzyme cuts the vector, and the insert is then joined to it by DNA ligase. A vector is a DNA carrier, commonly a plasmid, used to carry a desired gene into a host cell. First, the chosen restriction enzyme recognizes a particular DNA sequence and cuts the vector. The insert is prepared with compatible ends. The insert is placed with the cut vector, and DNA ligase seals the sugar-phosphate backbone. Option A is correct because it gives the normal order. Option B is wrong because an insert does not first become protein; it must first be joined to a vector. Option C is biologically meaningless because a vector does not become water. Option D reverses and confuses enzyme and DNA events; DNA is not formed after an enzyme simply ends. Memory cue: cut first, join second—restriction enzyme cuts and ligase joins.