Germs are tiny living organisms that are too small to see without a microscope. They include bacteria, viruses, fungi, and protozoa. These microorganisms live in many places, including air, water, soil, and inside plants and animals. Some germs live on the human body without being noticed.

Germs are found everywhere on Earth, from deep oceans to high mountains. They have existed for billions of years, long before humans appeared. Some germs can affect people, animals, or plants, while others are part of natural environments. They can spread through touch, air, or surfaces in everyday settings.