Science has brought about many changes in the means of transport. In the olden days, people travelled on foot or on the backs of animals. Vehicles drawn by animals, such as the bullock carts and the tonga, were also used.

However, today engines powered by electricity, gasoline, or diesel are being used to run modern vehicles. We are all familiar with land vehicles such as cars, buses, trams, trucks, and trains. 

Aeroplanes, helicopters, and jets fly in the air. Even present-day ships are very advanced. Rockets can now fly even to the moon and to some of the planets in our solar system. Lifts take people up and down multi-storeyed buildings.

There is no need to burden animals any more because of modern means of transport.