complementary strand. noun, Biochemistry. 1. either of the two chains that make up a double helix of DNA, with corresponding positions on the two chains being composed of a pair of complementary bases. 2. a section of one nucleic acid chain that is bonded to another by a sequence of base pairs.
The teething process. Most babies start teething at around six months. However, all babies are different and the timing of teething varies. Some babies are born with their first teeth. Others start teething before they are four months old, and some after 12 months. Early teething should not cause a child any problems, unless it affects their feeding. A rough guide to the different stages of teething is:
Kids start to lose their primary teeth, or baby teeth, at about 6 years old. This begins a phase of permanent tooth development that lasts over the next 15 years, as the jaw steadily grows into its adult form. From ages 6 to 9, the incisors and first molars start to come in. Between ages 10 and 12, the first and second premolars, as well as the canines, erupt. From 11 to 13, the second molars come in. The wisdom teeth (third molars) erupt between the ages of 17 and 21.