Matter cannot be created or destroyed in chemical reactions. This is the law of conservation of mass. In every chemical reaction, the same mass of matter must end up in the products as started in the reactants. Balanced chemical equations show that mass is conserved in chemical reactions.
If the allele frequency of a gene for brown fur is increasing from 15 to 25 percent, the population of the bears is evolving.
the tail bone connects to the spine :)
