Affect is a psychological term for an observable expression of emotion. A person's affect is the expression of emotion or feelings displayed to others through facial expressions, hand gestures, voice tone, and other emotional signs such as laughter or tears. Individual affect fluctuates according to emotional state.
There are over 3,000 different species of cockroaches-some are considered pests while others are beneficial in their natural environment. The three main types of cockroaches commonly found in homes in South Africa include the German cockroach, Oriental cockroach and American cockroach.
Scientific Name: Blattella germanica. 1  Identification: The German cockroach is the smallest of the common cockroaches, and the most prevalent. 2  Length: 1/2 to 5/8 inch long. 3  Body: wide and flat.4  Color: tan to light brown to dark brown, with two dark brown stripes on the body.f the approximately 50 cockroach species that occur in the U.S., the German and American cockroaches are two of the most common species that infest homes, restaurants, hotels and other establishments. There are, in fact, few, if any, locations in the U.S. where these species are not found.