Explanation:
Your heart has 4 chambers. The upper chambers are called the left and right atria, and the lower chambers are called the left and right ventricles. A wall of muscle called the septum separates the left and right atria and the left and right ventricles. The left ventricle is the largest and strongest chamber in your heart.
I would look inside the nucleus (B) - that's where DNA is located. It's also called nuclean DNA because of this. The DNA is found in Chromosomes, which are kind of "packages" of DNA.
The answer is acquired immunity. When you come down with an illness, your body develops the ability to fight it.
A nutritionist at a children's hospital or in your community