The thymus is positioned in the upper chest cavity above the heart. Thymus. The thymus gland is the main organ of the lymphatic system. Located in the upper chest region, the primary function of this gland is to promote the development of specific cells of the immune system called T lymphocytes. T lymphocytes or T-cells are white blood cells that protect against foreign organisms (bacteria and viruses) that have managed to infect body cells.
How long does it take for the Earth to rotate on its own axis ? The time it takes the Earth to rotate once is called a day (24 hours). The actual rotation time is a little less, about 23 hours and 56 minutes. Why do we have Day and Night?
Best Answer: The quick answer is that's how long it takes for the Earth to rotate once relative to the rest of the universe, 23 hours 56 minutes. Because the Earth is also orbiting the sun in the same direction as it is spinning, it has to spin a little extra to catch up and face the sun as it did the day before, taking 4 extra minutes, or 24 hours to do it.