A proposed explanation for a wide range of observations and experimental results that is supported by a wide range of evidence. ... Most factors are held constant in a scientific experiment because you can only change one factor in an experiment so if you notice something, you'll know what caused it.
Gross motor - controlling the head, sitting, crawling, maybe even starting to walk. Fine motor - holding a spoon, picking up a piece of cereal between thumb and finger. Sensory - seeing, hearing, tasting, touching and smelling. Language - starting to make sounds, learning some words, understanding what people say.
