Questions 16-20. Read the passage and choose True or False for each sentence.

Astronomers and other scientists constantly research and explore space. One of the most intriguing questions they hope to answer one day is whether life exists on other planets. Despite a lot of research in outer space, scientists have not yet been able to find evidence of life forms on any other planet other than Earth.

Earth is very hospitable, which makes living here easy. Earth has water, which living creatures need to survive. Earth also has an atmosphere that is neither too hot, nor too cold. Its distance from the sun provides Earth's inhabitants with the proper amount of warmth, sunlight and energy. Although there may be other planets that have some of Earth's hospitable features, so far scientists have not found any with all of the features they believe necessary to sustain life. Earth remains one of a kind!