Changes in the dna are called mutations. They can occur spontaneously. Mutations can only be passed down in gametes--sperm and egg cells. with Darwins theory at mind a mutation needs to pass the test of natural selection to remain in the gene pool. So purposly making mutation or altercations may end in diseases/illnesses or in some cases death because they body can not take it.....hope this helps if it doesnt im sorry!
Answer:
They are ammonia, urea, uric acid, and creatinine. All of these substances are produced from protein metabolism.
Metabolic waste is the left over products of both catabolism and anabolism. This waste includes salts, phosphates, sulfates, excess substances, and nitrogenous wastes like urea which are eliminated through urine.
