What are secondary sex characteristics?What is the 2nd sex characteristic??

Secondary sex characteristics are those characteristics we
associate with male and female characteristics after the onset of puberty. After the
primary characteristics of egg or sperm production, secondary characteristics develop as
a result of the male and female sex hormones testosterone and estrogen, respectively. In
males, the secondary characteristics include a deeper voice, body and facial hair, a
bigger size and growth of the sex organs. In females, a larger hip area(for later
childbearing), breast development, pubic hair, menses, a larger uterus and feminine body
shape. In most animals where there are males and females, secondary sex characteristics
may provide a selective advantage for mating. Male peacock feathers that are displayed
as part of a courtship ritual are an example. Male lions have an impressive mane. These
can help attract females to males to insure reproduction occurs.