Answer:
Nucleus
Explanation:
It is enclosed by a nuclear membrane perforated by numerous pores. It regulates the activities of the rest of the cell. It contains chromosomes which carry the hereditary materials. One or more densely staining bodies called nucleoli is present in the nucleus. It is site for synthesis of ribosomes
The second and third one I believe
converting food into smaller molecules
B: Antigens
Explanation: Antigens itself are the invaders that causes an infection or a disease in living organism. They do not protect against invaders in non-specific response as they themselves are the ones who are invading the body.
Digestive enzymes are the enzymes that act on a particular substrate for its action at a particular PH.
Stomach acid is the hydrochloric acid that keeps the PH of the stomach low and prevents the growth of unwanted pathogens.
Lysosomes have digestive enzymes in it. It performs the process of phagocytosis.
Explanation:
Organisms form species if they live together and can reproduce offspring. A group of organisms of the same species living in the same place at the same time is called a population. If we put populations of different species together, that's called a community. So, a community needs groups of different species to exist.
