@@MathAndScience Hello sir I want to say that I am appreciating your work it is very useful for who whant to learn something! I have a son so I have to prepare myself with this knowledge to explain to him when he will learn these things and because I didn't understand I'm that time when I went to school now I find them amazing facts ! In particular chemistry ! Greetings from the UK ! By the way I have also not too much hair remains :))
