Question: if cells multiply/ copy each other then how are scars formed?

Rebecca Moon answered on 12 Jun 2019:

A scar forms in the skin where there has been a break in the skin. Although theoretically the skin cells could just replicate to fill the hole, the process would be too slow and wound healing is a more complex process which aims to fill the defect rapidly and prevent infection entering the body now that the skin is broken as the skin is an important barrier to infection. When a wound is created, bleeding occurs which results in increased delivery of platelets to the site. These help clot so that excessive blood is not lost. Inflammation then occurs, which results in dilatation of the capillaries in the area and results in the delivery of several factors to the site of the wound. This includes white blood cells and antibodies to fight any infection that might enter through the wound. Fibroblasts then deposit a mesh of collagen and proteins through which blood vessels grow and extend. This mesh then contracts to bring the edges of the wound together and new epithelial (skin cells) start to grow within and over the mesh. Scar tissue is not typically as strong as the original tissue