Answer:
Because the gene is an inheritance of our ancestors, weight is something you gain or lose depending on how balance your health is. The reason why our weight can't be controlled by the gene is because the gene has different traits coming from each parents(50%) and grandparents(25%), and either parents has different weight, so it will be hard for the gene to capture one specific weight from both sides.
Answer:
Can be used for simple experiments at home or in the classroom
Avoid carcinogens (like smoking residues..etc), eat healthy and sleep well in order to maintain a strong immune system