Brownsville is a borough in Fayette County, Pennsylvania, United States, officially founded in 1785 located 35 miles (56 km) south of Pittsburgh along the Monongahela River.
2nd Item Specification: Given a group of organisms and a key, classify organisms based on observable characteristics. Depth of Knowledge Level 1. 1  A tool used by scientists to identify unknown organisms based on observable characteristics is called a. 2  dichotomous key.
The immune system is the set of tissues which work together to resist infections. The immune mechanisms help an organism identify a pathogen, and neutralize its threat.The immune system can detect and identify many different kinds of disease agents. Examples are viruses, bacteria and parasites.The immune system can detect a difference between the body's own healthy cells or tissues, and 'foreign' cells.he immune system can detect a difference between the body's own healthy cells or tissues, and 'foreign' cells.