Microorganisms are tiny. They are so small they can only be seen with a microscope. Yeast is a helpful microorganism which makes bread rise. Bacteria is a microorganism which breaks down plants ...

What is a vector? A vector is a vehicle that carries and transmits a disease to its host organism. Vectors include animals and microorganisms that transmit different diseases. The most common ...

Vector Any organism that can spread a disease is called a vector. Many farmers think tuberculosis in their cattle can be spread by badgers.