An experimental group is the group in an experiment that receives the variable being tested. One variable is tested at a time. The experimental group is compared to a control group, which does not receive the test variable. In this way, experimental groups are used to find answers in an experiment.
1 At around 9 months of age, babies begin to pull themselves up to a standing position. 2  By 10 months of age, a baby should be able to grasp objects with thumb and forefinger.
It's no wonder: red is among the colors babies see best once their color vision first kicks in, at about 3 months. A newborn doesn't see in color at all, thus her early fascination with black-and-white patterns and playthings. Her color vision is fully in place by 4 months.