ІІ. Fill in prepositions where necessary.
1. Chemistry is the study ... matter and its changes.
2. All the matter is composed ... fundamental units called atoms.
3. The science ... chemistry is important ... improving the standards ... living.
4. The nucleus ... the atom is composed ... two particles called protons and neutrons.
5. Chemistry provides employment ... a large variety ... people.
6. The simplification ... chemical problems is made ... classifying matter.
7. The behavior ... the four forms ... matter can be explained ... the fact that all matter consists ... particles ... motion.
8. The universe is made ... more than 90 elements.
9. Chemistry involves ... the study ... chemical elements and how they combine.