The thyroid gland is a vital hormone gland. Its plays a major role in the metabolism, growth and development of the human body. It helps to regulate many body functions by constantly releasing a steady amount of thyroid hormones into the bloodstream.
The
term used to describe features that has been modified from an ancestral form is
evolution. It is a biological change by which descendants come to differ from
their ancestors. In addition, an individual inherits features called traits from its parents through genes and these genes can
produce a new trait in their offspring.