In what part of a cell does the disease giardiasis start in

Giardia is a microscopic parasite that causes the diarrheal illness known as giardiasis. Giardia (also known as Giardia intestinalis, Giardia lamblia, or Giardia duodenalis) is found on surfaces or in soil, food, or water that has been contaminated with feces (poop) from infected humans or animals.

answer; /// i believe that the correct answer is (c); ///when the lungs expand, they fill with air from the atmosphere;

proteins is the answer