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:
Teething usually begins around 6 months of age. But it is normal for teething to start at any time between 3 months and 12 months of age. By the time your child is about 3 years old, he or she will have all 20 primary teeth. The lower front teeth usually come in first. Upper front teeth usually come in 1 to 2 months after the lower front teeth.