How is it that the entire diversity of life can be spelled out using only four different bases?

Various genes differ from each other with respect to the sequence of nucleotides.

Explanation:

DNA is the molecule that serves to store genetic information. DNA is a polymer of deoxyribonucleotides. There are four types of deoxyribonucleotides that differ from each other with respect to the nitrogenous base. A deoxyribonucleotide can have either of four bases: adenine, guanine, cytosine, and thymine.

Genes that regulate various traits differ from each other in the sequence of nucleotides. Various combinations and sequences of nucleotides result in a large number of genes which in turn account for diverse types of proteins to impart a variety of genetic traits to the organisms.

when the displaced particles are perpendicular to the direction the wave travels, is called a transverse wave, whereas in longitudinal wave the displace practices are parallel to the direction of the wave.

in the given image:

first image shows - longitudinal wave

second image shows - transverse wave

third image shows - longitudinal wave

fourth image shows - longitudinal wave