The secondary response involves mainly memory cells, this is the response that occurs on the second entrance of a microorganism or virus that has been encountered before and dealt with by the primary response.he primary immune system is also called innate immunity or auxiliary immunity because it is unspecific and present in everyone. These include physical and chemical barriers t â¦ hat protect the body from many different microscopic organisms. --Skin (and hair) acts as a large physical barrier.
The twin towers of the World Trade Center (WTC) collapsed on September 11, 2001, as a result of being struck by jet airliners hijacked by terrorists affiliated with al-Qaeda during the September 11 attacks.
Hyatt Regency walkway collapse. The Hyatt Regency walkway collapse took place at the Hyatt Regency Kansas City hotel in Kansas City, Missouri, on July 17, 1981. Two vertically contiguous walkways collapsed onto a tea dance being held in the hotel's lobby. The falling walkways killed 114 and injured 216.