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.
Cockroaches are insects of the order Blattodea, which also includes termites. About 30 cockroach species out of 4,600 are associated with human habitats. About four species are well known as pests. The cockroaches are an ancient group, dating back at least as far as the Carboniferous period, some 320 million years ago. Those early ancestors however lacked the internal ovipositors of modern roaches. Cockroaches are somewhat generalized insects without special adaptations like the sucking mouthpar