What is a lunar calendar and who created it?

The lunar calendar became the basis of the calendars of the ancient Chinese, Babylonians, Greeks, and Jews

Greek astronomers also devised rules for intercalations to coordinate the lunar and solar years. It is likely that the Roman republican calendar was based on the lunar calendar of the Greeks

correct answer is option a.

tropopause, stratopause and mesopause have all in common aspect that is point of maximum temperature in its layer of the atmosphere. all layers of atmosphere observe abrupt change in temperature. tropopause is the boundary between troposphere and stratosphere. stratopause is the boundary between stratosphere and mesosphere. mesopause is the boundary between mesosphere and thermosphere. these all boundaries are ranges between altitude of 0 to 80 km.

answer; polycythemia is the correct answer;