Studies on immune responses in afferent and efferent lymph of lymph nodes draining the tissues have contributed to the concept that primary immune responses are generated in the lymph nodes with a delay before antigen-specific effector cells arrive at the affected tissue.
Lightning strikes the ground approximately 25 million times each year in the U.S. According to the NWS, the chance of an individual in the U.S. being killed or injured during a given year is one in 240,000. Assuming an average life-span of 80 years, a person's odds over their lifetime becomes one in 3000.
There are an estimated 25 million cloud-to-ground lightning. flashes each year in the United States, nearly 650,000 of which. occur in Illinois alone. Lightning can be fascinating to watch, but it is also extremely dangerous â it is the underrated killer. Few people really understand the dangers of lightning. Many. people donât act promptly to protect their lives, property, and. the lives of others.