Here, the first part of the text has been divided into 8 segments, numbered from 1-8. Click on the segments that contain at least one error (there may be more than one error per segment). Look at the solution before you do the next question.
(1) The universe (2) is a mystery (3) since a lot of centuries. (4) There is two problems in cosmology.(5) The first mystery (6) is lack of mass. (7) We explain it (8) with the dark matter.
