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.
1962 â Bertrand Goldberg. Goldbergâs twin towers in Marina City, on the bank of the Chicago River in downtown Chicago, marked the beginning of including reinforced concrete in modern skyscrapers during construction. At the time of their construction in the 60âs, the towers set the height record at 588 feet.