Question

why are there lines on our palm ? what are they call ? when are they made? what's use of it?

Answer 1

The lines on our palm are there because of our scrunch into a fist or other complex shapes without excessive stretching etc. ex - holding a cup. These lines start developing before birth, in a mother's womb. inside the womb A baby's hand is closed making a fist which causes those lines.
They are known as palmar flexion.
These lines start developing before birth, inside a mother's womb.
According to science they help the palm to squeeze and stretch and in some cases help in identification too.

Hope this helps....☺