1. The poison from the bite of the black widow spider causing unbearable pain, stiffens the muscles of the abdomen, causing death to some of its victims.
2. Mosquitoes can cause diseases such as malaria, yellow fever and sleeping sickness.
3. Mosquitoes pick up germs and pass them on to people they bite.
4. Flies, too, can spread diseases such as cholera, dysentery and typhoid fever.
5. When we keep our surroundings clean, we keep off insects which live and breed in dirty places. A clean place will be free of dirt, free of insects and therefore free of diseases