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.
This is why the recommended age for weaning is now 6 months. As for the blue baby syndrome, as Sarah mentions - the only conditions I am aware of are related to congenital heart defects and rhesus disease - and I am not aware of any relationship between food and these conditions.