The variation of gene expression that is not related to the variation of the DNA, is transmissible, and is reversible is described as

What amino acid is coded for by this sequence after the mutation

All phases of matter may have a fixed mass

Many body systems work together for proper functioning of the body and to maintain internal homeostasis. the works to break down food eaten before exercising. the takes in the nutrients obtained from the food. the body sweats as a mechanism to cool off, because the is working to flush out toxins.