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.
Baby teeth are also called primary or milk teeth. They have very thin roots that look like thread. Your baby will start to get teeth somewhere around six months of age, but the first tooth can appear anytime between three and twelve months of age. Your child should have all 20 baby teeth by around age three â 10 on the bottom and 10 on the top.