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.
Normally, however, the result is rain, wind, lightning, and thunder. Without lightning, there would be no thunder in thunderstorm.. Thunder is the noise lightning makes as it travels through the air. Lightning occurs during all thunderstorms (though not every time it rains). During a storm, it strikes Earth 100 times each second. More than just a dazzling light show, lightning causes billions of dollars in damage each year. Lightning forms when updrafts of air carry water droplets, which have a charge, upward to heights where some freeze into ice and snow particles. They form a cloud.