Answer:
Every day we are alive, humans encounter potentially harmful disease causing organisms, or “pathogens”, like bacteria or viruses. Yet most of us are still able to function properly and live life without constantly being sick. That’s because the human body requires a multilayered immune system to keep it running smoothly. The two main classes of the immune system are the innate immune system and the adaptive immune system, or “acquired immunity”. In this article, we’ll discuss the first line of defense: the innate immune system.