For rain and very light snow, 2WD will likely work fine, and for most vehicles, front-wheel drive is the preferred setup. (For performance cars, RWD is preferred, but AWD, if available, can increase traction. AWD is fine for most normal snow conditions or for light-duty, off-pavement excursions.
Microorganisms that cause diseases are called pathogens. They are specialised to infect body tissues where they reproduce and cause damage that gives rise to the symptoms of the infection. The body fights back by mobilising its immune system to fight off the infection.
Microbes cause infectious diseases such as flu and measles. There is also strong evidence that microbes may contribute to many nonâinfectious chronic diseases such as some forms of cancer and coronary heart disease. Different diseases are caused by different types of micro-organisms.