How many different types of cold viruses are there?

Explanation

There are around 200 different cold viruses, which spread via droplets (sneezing and coughing). Droplets from a sneeze can linger in the air for an hour or more, while they can survive on various surfaces for up to several hours. Smooth metal surfaces (handles, railings, poles on the bus or train, etc.) transfer viruses more easily than rough surfaces, which trap the viruses.