We all know that the existence and development of all living things are affected by environmental factors, one of the most influential factors is temperature. Suitable temperature can help living things grow quickly, but temperature that is too low or too high can cause living things to grow slowly, or even be killed by the temperature.

The world has experienced many pandemics, each one leaving behind serious human and economic consequences. When does a disease become a pandemic?

We are experiencing days full of anxiety about the acute pneumonia caused by the new strain of coronavirus (Covid-19) when the number of infected people is constantly increasing, especially the epicenter in Wuhan city, China. The disease has spread to many countries around the world, people are afraid that this disease will become a new pandemic of humanity. In fact, we humans have experienced many major epidemics around the world, with very dangerous levels of destruction.

People do not always get sick from viruses, even though they are exposed to viruses every day in their environment. This is because the body's immune system can handle most of this. It is only when the body is exposed to a new virus for the first time or is exposed to a large amount of the virus that the body becomes sick.