An antigen causes the body to make antibodies.
Answer:
Protein containing food like meat, egg and chicken etc is the muscle building food.
Explanation: Protein containing food such as meat is the food substance that contains the nutritive materials which helps in the build of muscles in the human body , but does not contain the macromolecules that provides quick energy. Meat which is a good source of protein and we know that protein is the main nutrient which is responsible for the building of muscles in the human body.
The answer is the fourth one.
Protons are fixed in the nucleus
It is the excretory system
