Answer:
bacteria-Some bacteria help to digest food, destroy disease-causing cells, and give the body needed vitamins. Bacteria are also used in making healthy foods like yogurt and cheese. But infectious bacteria can make you ill. They reproduce quickly in your body.
Virus-A virus infects your body by entering healthy cells. There, the invader makes copies of itself and multiplies throughout your body. The new coronavirus latches its spiky surface proteins to receptors on healthy cells, especially those in your lungs.
fungi-When fungal organisms enter the body and the immune system is compromised these fungi grow, spread and invade into tissue and spread locally. Some organisms, especially yeast and some molds, can invade the blood vessels and cause infection in the bloodstream and distant organs.
Parasite-When the worms live in the body they can cause sickness. They may get into the stomach and gut and eat the food before the body has digested it. This means that the body does not get enough nourishment. Sometimes the worms will find their way into other parts of the body, such as the blood or liver.
