Have you ever dreamed of traveling in space? It was impossible a hundred years ago, nor was it 50 years ago. With the coming of the Space Age, man’ s dream of visiting the moon has come true. The journey to the moon has been the first step towards future explorations in space. The distance between the moon and the Earth is very short indeed when compared with the distances between Earth and the other planets. Mars, the nearest planet to Earth is of miles away ! Traveling to the planets or travels between planets will be man’ s next aim. Such travels will be more difficult than the trip to the moon and certainly more exciting. Recently, two American unmanned spacecraft, Vikings 1 and 2, landed on Mars in an attempt to discover whether that planet had any life on it. So far the presence of life on Mars has neither been proved nor ruled out. Russian space-probes have discovered that the surface of Venus is so hot that it is almost certain that there is no life there. Also the atmosphere of Venus is extremely, dense and the pressure is nearly a hundred times greater than the pressure of the Earth’s atmosphere. Scientists believe that in the future, space stations can be built in space. These stations can act as stop-over points in space. Spacecraft can refuel at these stations and get their supply of air, food and water. Spaceships of the future will be bigger and faster. They will be able to carry passengers for trips to the moon or planets. Man may in the future find planets which have the same conditions as those we have on Earth, and make them his home. However such a possibility is still in the distant future. At the same time, Man should realize that the Earth will be his only home for a long time and begin to value and care for it. Which of the following statements is true?