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.
From 9 months through age 2 1/2, the color trend lightened. After age 3, hair color became progressively darker until age 5. This just means that your babyâs hair may change shades a few times after birth before settling on a more permanent color.