Across
- 5. There have already been several technological ____________this century, such as the electric car and the tablet computer.
- 7. Blood tests and X-rays can help doctors ___________ diseases.
- 8. Bottles are useful _____________ for water and other liquids.
Down
- 1. Scientists can study the day-to-day movements of an animal by using a tracking _____________.
- 2. Before refrigerators were invented, people could not easily ____________ fresh meat.
- 3. One __________ of solar power is that it is renewable.
- 4. The wheel is one of the most _____________ inventions of all time. Without it, we would probably have to walk or ride animals to travel long distances.
- 6. Research ___________ that the global demand for energy is expected to triple by 2050.