Sometimes one hand clenched fist and one hand opened, is it normal?

Answer b answer analysis test analysis: veins are generally distributed in shallow parts of the body. One hand holds the wrist of the other hand, and then the gripped hand makes a fist and opens it several times. I found that the "blue veins" on the back of my hand are actually veins. Test center: the knowledge point of this question is the characteristics of veins, and the answer is based on the analysis that veins are generally distributed in the superficial part of the body.