The early sunrise and late sunset are due to atmospheric refractions.
True
The light initial journey is through vacuum and then through the atmosphere of the earth and then it is finally seen by us. In this case, the vacuum will be a rare medium and the earth's atmosphere with all its temperature changes, winds, different gases, will be a denser medium in comparison.
During sunrise, when the sun is just below the horizon, our atmosphere causes the light rays to bend and we see the sun early. Similarly, at sunset, the apparent position of the sun is visible to us and not the actual position but apparent position due to the same bending of light rays.