Quick Answer. An experimental variable is something that a scientist changes during the course of an experiment. It is distinguished from a controlled variable, which could theoretically change, but the scientists keep constant. Continue Reading.
While you were pregnant, your baby developed tooth buds, the foundation for baby teeth (also called milk teeth). Very rarely, a baby is born with a tooth or two, or grows a tooth in the first few weeks of life. But the vast majority of babies sprout their first tooth sometime between 4 and 7 months old.
By age eleven to thirteen, the process should be complete and all of his baby teeth will be gone. The secondary or permanent teeth soon begin erupting as your child loses baby teeth. This process isn't complete until your child gets his third molars or wisdom teeth at age seventeen to twenty two years of age.