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.
They go from a small amount of melanin, which you'll remember causes eyes to be blue, to a larger amount which means they'll be a different color. Usually this happens around six months, but eyes can change color up to about three years old. And the reason this only happens for Caucasian babies is because they tend to be born with less pigment than other ethnicities.