What Is the role of antibodies in the human body?

Protection

Explanation:

Antibiotics play a very important role in the immune system. Whenever antigen or foreign particle enters in the body, B-lymphocytes identify that antigen and produce antibody against that specific antigen. Which kills that antigen. It also has another very important role, as whenever the next time the same antigen enters in body, the body already has antibodies against it. And kill that antigen immediately.

the correct answer is - d. china has a large and growing population.

the fact that china has a large (the biggest) population, and it is still growing, doesn't hinder the agriculture production in the country. in fact, it can for increased production in the agriculture, since there's more labor force, as well the sheer mass of people produces lots of scientists that come up with new inventions as to how to improve this sector. nice example is the inner mongolia region in china, in general dominated by the gobi desert, but few scientist came up with a nice idea as to how to make the region productive by using plants that are very resistant to droughts, so lots of people have been employed, and the region is becoming greener and greener each year, and the production of food in this region is also increasing.