Different systems<span> of the body have different functions. For example, your </span>digestive system<span> is responsible for taking in & processing food, while your </span>respiratory system—working<span> with your</span>circulatory system<span>—is responsible for taking up oxygen and getting rid of carbon dioxide. Hope this helps</span>
The meaning is, "the taking in of matter by a living cell by invagination of its membrane to form a vacuole."
D. Enzymes and antibodies