Change the forms of the given words to make lexically correct sentences

1. Elon Musk is a very
   [ ]
   person: he is often in the news.

2. He is really smart, educated and
   [ ].

3. The job of a bioengineer requires a really deep
   [ ]
   of different subjects.

4. The
   [ ]
   of aliens hasn't been proved yet.

5. Some people believe that holes in the ozone layer are a(n)
   [ ]
   problem and cannot ruin life on Earth.

6. [ ]
   technology cannot allow us to be 100 % eco-friendly.

7. [ ]
   is the first stage in any process.

8. Financial
   [ ]
   predict economic recession in the near future.

9. To be successful in the stock exchange, you'll have to study plenty of technical data and
   [ ].

10. The
    [ ]
    of space research cannot be overestimated.

11. More
    [ ],
    all the things we know now can help us save the environment.

12. A: Billy, I'm really sorry about the book. How could I have forgotten to bring it?

    B: Don't bother. It's [ ].