The correct answer is A. Alkali metals.
I hope this helped
Because your Teeth are composed of calcium, phosphorus, and other minerals. ... But bones are still not as strong as teeth. The hardest part of the human body ,teeth mostly consist of a calcified tissue called dentine. The tooth's dentine tissue is covered in enamel, that hard, shiny layer that you brush.
_________ is designed to protect you from injuries to your head, face, eyes, ears, hands, feet, respiratory tract, and body
the answer to this question, is B personal protective equipment
hope this helps :D
You can't really describe it but this is what it looks like http://www.chemspider.com/Chemical-Structure.453291.html
