C) The scientist who saw the solution on a bus

The chemist ‘Kekule’ is famous for having discovered a lot about how 1____ atoms and 2____ molecules are arranged.

3____ first discovery happened when he was riding on a bus, one evening in about 1855, thinking about other things. Suddenly, he saw 4___ atoms dancing before his eyes. Then one atom joined another one to make 5____ chain. When he got off the bus he understood how 6___ atoms join together to make molecules.

3.Fill in the gaps with the, a, or–.Underline the correct word.

__ Scientists do __ lot of __ research in order to find __ cues for various diseases.

__ lot of money is/arespent on ___ equipment every year, but ___ information collected is/areinvaluable.