By the year 2010, 17.8 million youths aged 16-19 will work, up from 16 million in 2000, according to government forecasts. Young workers suffer a disproportionate share of injuries and fatalities, especially in the first year on the job. In 2006, 30 youths under 18 died from work-related injuries.
A mutation may or may not affect the amino acid sequence. A mutation may or may not affect the phenotype. Some specific mutations in a gene may have more adverse affects than other mutations in the same gene. A mutation is not necessarily bad. It may even be good. A mutation may enhance or positively change the function of the protein produced by the gene.
Before the Industrial Revolution, a mutation which changed light moths into dark moths was an unfavorable (harmful) mutation, whereas during the dark years it was a favorable (helpful) mutation. To see why most mutations are neither harmful nor helpful it helps to know a bit about what mutations actually are. A mutation is a change in the genetic material that controls heredity. The genetic material is contained in chromosomes. Plants and animals have two copies of each chromosome whereas bacteria only have one copy.