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.
1 Although an infant's color vision is not as sensitive as an adult's, it is generally believed that babies have good color vision by five months of age. 2  Most babies start crawling at about 8 months old, which helps further develop eye-hand-foot-body coordination.