1 the set of exogenic (physical, chemical and biological) processes that alter the physical and chemical state of rocks at or near the earth's surface.  intensity of most weathering decreases with depth, because variations in temperature and moistures decrease with depth.
A gene is a segment of nucleic acid that contains the information necessary to produce a functional product, usually a protein. Genes consist of a long strand of DNA (RNA in some viruses) that contains a promoter, which controls the activity of a gene, and a coding sequence, which determines what the gene produces.
Genes contain exons which are regions coding for proteins and which are interrupted by the unused sequences called introns. Exons have been found to include both sequences coding for amino acids and untranslated sequences. The introns are removed and the exons are joined together to form the final functional mRNA.