The answers are well explained & appreciated . The graphs & photos represents snail population to be significantly different in 1980s than that of 1871. The shells of the snails are thicker now than that of previous one. There exist change in population along with modification i.e, evolutionary changes. Above written answers satisfies the question. Solution The answers are well explained & appreciated . The graphs & photos represents snail population to be significantly different in 1980s than that of 1871. The shells of the snails are thicker now than that of previous one. There exist change in population along with modification i.e, evolutionary changes. Above written answers satisfies the question..