NEET BIOLOGY

Detailed explanation-1: -Infection, often the first step, occurs when bacteria, viruses or other microbes that cause disease enter your body and begin to multiply. Disease occurs when the cells in your body are damaged-as a result of the infection-and signs and symptoms of an illness appear.

Detailed explanation-2: -Infectious diseases are caused by pathogens, which include bacteria, fungi, protozoa, worms, viruses, and even infectious proteins called prions. Pathogens of all classes must have mechanisms for entering their host and for evading immediate destruction by the host immune system.

Detailed explanation-3: -Living, single-celled organisms that can reproduce on their own cause bacterial infections. Only a few types of bacteria cause illness in people. An organism that’s not made up of cells causes viral infections. Viruses always need to infect humans or other living things to create more copies of itself.

Detailed explanation-4: -A pathogen is a living thing that causes disease. Viruses and bacteria can be pathogens, but there are also other types of pathogens. Every single living thing, even bacteria themselves, can get infected with a pathogen.