1. Scientists have made many important new .......of the depth by using modern devices.(discover/ discoveries)

2. Community police have made a very positive.............to crime prevention.(contribute/ contributions)

3. They are investigating the............disappearance of a young woman. (Mystery/mysterious)

4. By the age of eighteen he was completely...........of his parents.(dependence/ dependent)

5. The...........of the seabed is being carried out (investigate/ investigation)