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.
A child gets two sets of teeth. The first set, baby teeth, starts to grow when the child is a baby. The second and last set grows in at school age. They are the permanent teeth. Permanent teeth should last a lifetime.A child grows his first baby tooth at about 7 months of age.It is usually a front one.he remaining baby teeth grow in over the next 24 months. By the time the child is 30 months old, there will be a total of 20 baby teeth in his mouth, 10 on top and 10 on the bottom. Most permanent teeth form under the baby teeth.