According to the online content article about days and nights on earth, why does the length of a day change throughout the year? a. because the sun revolves around the earth b. because the earth’s axis is tilted c. because it takes a year for the earth to rotate once d. because the earth’s orbit is not elliptical

The correct answer is - B. because the Earth's axis is tilted.

The Earth's axis is tilted, and that is the main reason why we experience changes in the length of the days and nights throughout the year. By being tilted, the Earth is enabling one part of it to receive more sunlight in one half of the year, while the other part receives less, which makes the one part having longer days and shorter nights, while the other longer nights and shorter days. The things change in the other half of the year, when the part that received more sunlight receives less, and the one that had less now has more, so the length of the days and nights switches.