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.
Six people were killed and thousands  evacuated. The destruction of the Twin â¦Towers took place on  September 11, 2001, and resulted in the loss of over 2750 lives,  including the passengers on the two hijacked aircraft that were  crashed into the towers. 4 people found this useful.