1. Science is important for most people living in the modern world for a number of reasons.
2. On the other hand, they have also helped to keep the peace in research which has improved life of people. (насчёт in не уверена, тут несколько может подойти в принципе).
3. We can begin to learn to share the resources of the knowledge provided to us by science.
4. In some cases, such as technology of taking salt from ocean water, technology may be essential for our lives on Earth.
5. The study of the natural world may help improve life of many people all over the world.