How can you see virginity of female?

Yes it can be seen as the hymen covers the vagina.

No the hymen is not a sing of virginity. It can stretch without breaking and if she's born without one or it has broken other ways there is no way of knowing.

If a girl do regular sex or have done sex many times then her vocal cord becomes c shape as boys and voice also changes. Also there will be stripe mark in there neck.

All these occures because of stimulation of vagus nerve and occure only girl is enjoying the intercourse not in case of rape.