Open the combination lock using the old combination. Remove the u-bar from the lock body so it's in the Unlock position. Use a screwdriver to open the anti-dust cover on the back of the combination lock. Align the old combination numbers to the guide points.
A base pair (bp) is a unit consisting of two nucleobases bound to each other by hydrogen bonds. They form the building blocks of the DNA double helix, and contribute to the folded structure of both DNA and RNA.
Each nucleotide base can hydrogen-bond with a specific partner base in a process known as complementary base pairing: Cytosine forms three hydrogen bonds with guanine, and adenine forms two hydrogen bonds with thymine. These hydrogen-bonded nitrogenous bases are often referred to as base pairs.