How do immunoglobulin genes code for a seemingly infinite variety of antibodies?

Think of DNA-there are only 4 bases, but different combinations give infinite possibilities. And the same for amino acids and proteins. Immunoglobulins work on a similar principle. Different VDJ segments are combined for the heavy chain of an antibody. Different VJ segments are combined for the light chain. Other ways: Random nucleotides may be added or removed between the gene segments. There are also different combinations of light and heavy chains. Antibodies can be any of the 5 isotypes: IgA, IgM, IgG, IgE, IgD. I'm not going to go into detail as this answer would take too long to write. Do some literature searching on B cells, V(D)J recombination, RAG genes, class switching.

Well, both latitude and intensity of light affect temperature because, the higher the light intensity, the higher the temperature and since latitude is the measure of how close you are to the equator, then the closer to the equator you are, the higher the temperature is.