4/ Complete the sentences with the words in the box: challenged, discoveries, overcome, investigating, contribution, covered, conservation, entrapment, maintained, migrate 1. Scientists have made many important new________of the depth by using modern devices. 2. Community police have made a very positive______to crime prevention. 3. This new discovery traditional beliefs. Some whales are known to______into warm waters to bear their calves. 4. 75 percent of the earth surface is________by water. 5. Unless the biodiversity were_________marine life would be at stake. 6. Scientists are_______how the crash occurred. 7. Sperm whale populations are at risk due to hunting and their accidental in______fishing nets. 8. What can I do to________my fear of flying? 9. The government has just set up a wildlife___________project.