Week 5 Homework – Key The correct words are underlined. 1. Frayed electrical wires are potential fire hazards. a. probable b. unlikely 2. The velocity of the wind increases during the storm. a. sound b. speed 3. The conservation of natural resources, such as rivers and forests, is an important issue of our time. a. preservation b. observation 4. When the temperature dropped, vapour accumulated on the inside of the window. a. steam b. dust 5. Pasteur´s germ theory proved to be valid and was a major breakthrough in the history of medicine. a. false b. true 6. When the bottle was uncapped, all the pressure inside was released. a. set free b. increased 7. Energy is released by the fission of atomic nuclei. a. splitting b. combining 8. The cold on top of the mountain got more intense later in the evening. a. extreme b. moderate 9. An alloy is a fusion of two or more metals that makes a stronger metal. a. combination b. separation 10. The best way to solve a problem is to find the source. a. origin b. effects 11. Flemming revealed that his discovery of penicillin was accidental. a. made known b. kept hidden 12. The earth absorbs the water from the rain. a. drinks in b. gives off 13. The driver went in the reverse direction. a. identical b. opposite 14. Air is the medium through which sound travels. a. process b. environment 15. The old building was transformed into an emergency hospital. a. enlarged b. changed