Ответ:

The greatest invention of 20th century, undoubtedly, is the internal combustion engine. This invention made possible automobilization and drove many countries as US, Japan, Korea to the success and prosperity.  

The automobile made an impressive progress from being luxury privilege for a few to mass product, which had changed the world we see today.  

Military vehicles changed warfare in just 100 years so dramatically as it would not had been changed in the previous 1000.

Another greatest invention from the automakers started in 21st century with a development of modern electric vehicles, Tesla is being a bright example of this revolution. In fact, it was predicted, than in the next 10 years the most cars become hybrid or fully electric.

The environment is better protected, when people use electric instead an internal combustion engine. First experiments were made to make an electric propeller engine for the planes and unmanned drones.

In the next decade or so, the progress will make possible for the electric cars, bikes to be used more widely in the developed and third world countries. The barriers in terms of taxation are dropped in China, Indonesia, Thailand to encourage the usage of electric and hybrid vehicles.

The future looks bright for environmentally friendly transport.