Choose the correct word or phrase.

1. Finding enough food for the world's growing population won't be easy; it'll be a big ... . 2. The population on Earth has ... in recent years. 3. Many new shops and businesses are ... in the area. 4. We need to ... on transport costs. 5. The machine is ... by solar power. 6. Harry's busy job sometimes ... him of his energy. 7. The farm shop sells fresh ... such as beans, strawberries and corn. 8. Fuel prices are ... at the moment; prices have nearly doubled since last year.