Why must a puritine pair with a pyradine?

Pairing of a specific purine to a specific pyrimidine is due to the structure and properties of each ring and the three-dimensional fit between complements. Purine and pyrimidine are organic, aromatic ring compounds that act as the building blocks of nucleic acid. In DNA, purines occur as adenine and guanine, while pyrimidines occur as thymine and cytosine. In DNA base pairing, adenine pairs with thymine, and guanine pairs with cytosine

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.