Groups are determined by PRECIPITIN test, serologic test to measure a specific reaction between antigen (C carbohydrate, located in the cell wall) and antibody which results in a visible precipitate. Group A Streptococci (Streptococcus pyogenes) is among the most important human pathogens.
What is the leading cause of accident? Environmental, material, human number one cause of all auto accidents in the US - distracted drivers. get off the cell phone, stop texting, put the makeup away and set the sâ¦oda down and quit tuning the radio and reading the newspaper and and and pay attention to the road.
Causes of Down Syndrome. From what is known about the causes of Down syndrome, environmental factors and parents' behavioral activity do not seem to play a role. Most cases (approximately 92 percent) are caused by trisomy 21, which means each cell in the body has three copies of chromosome 21 instead of the usual two copies.