You should say:
What it is.
What it is used for.
What the advantages and disadvantages of it are.
THE MOST IMPORTANT INVENTION
1. Since its invention, the automobile has become one of the most important means of transport in the world. Automobiles have completely changed the lifestyles of almost all people in the world.
2. On the positive side, people can go anywhere by car more rapidly compared to on foot or riding a horse in the past. And thus people can realize their dreams of traveling to far off places.
3. On the negative side, automobiles are the main source of air pollution in the world. This creates the so-called 揼reen-house?effect, which leads to many serious environmental problems.
As for the applications of the automobile are concerned, I would like to highlight the following:
4. Firstly, it has totally changed the way in which we travel. In the past, animals like horses, mules, and camels were used for traveling and the transportation of goods. Compared to previous ways of traveling, automobiles are more comfortable and faster.
5. In addition, the automobiles have made it possible for us to transport large quantities of goods and people at one time. For example, mega-trucks and busses are well suited for these purposes.
6. Lastly, the invention of the automobile has resulted in many new industries being formed. The repairs and spare-parts industries for example, provide jobs to millions of people all over the world.