29.The portion of the electromagnetic spectrum between the 21 cm : 1777282
29.The portion of the electromagnetic spectrum between the 21 cm line of neutral hydrogen and the 18 cm line of OH is known as the ____________________.
30.The Miller experiment succeeded in creating ____________________.
31.The most important quantity necessary for life to form appears to be the existence of ____________________ on the surface of the planet.
32.The oldest easily identifiable fossils appear in sedimentary rocks that formed 3.4 billion years ago during the ____________________ period.
33.The Viking landers searched for life on ____________________.
34.The ____________________ is a region around a star where liquid water can exist.