To solve this problem, we need to identify the correct pair of terms and their functions from the given options. Let's analyze each option:$\newline \bullet$Option 1: Polymerases - Break the DNA into fragments$\newline$ - Polymerases are enzymes that synthesize DNA or RNA molecules from nucleotides, the building blocks of DNA and RNA.$\newline$ - They do not break DNA into fragments; instead, they are involved in the replication and repair of DNA.$\newline$ - Therefore, this option is incorrect.$\newline \bullet$Option 2: Nucleases - Separate the two strands of DNA$\newline$ - Nucleases are enzymes that cleave the phosphodiester bonds between nucleotides in nucleic acids.$\newline$ - They do not separate the two strands of DNA; rather, they cut DNA strands.$\newline$ - Therefore, this option is incorrect.$\newline \bullet$Option 3: Exonucleases - Make cuts at specific positions within DNA$\newline$ - Exonucleases are enzymes that remove nucleotide sequences from the ends of DNA molecules.$\newline$ - They do not make cuts at specific positions within DNA; that function is performed by endonucleases.$\newline$ - Therefore, this option is incorrect.$\newline \bullet$Option 4: Ligases - Join the two DNA molecules$\newline$ - Ligases are enzymes that facilitate the joining of DNA strands together by catalyzing the formation of a phosphodiester bond.$\newline$ - They are crucial in DNA replication and repair, as they join Okazaki fragments on the lagging strand.$\newline$ - Therefore, this option is correct.$\newline$The correct pair is Option 4: Ligases - Join the two DNA molecules.