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?
Just think of a top, or record, or wheel. All these things spin around a center point which we call an axis. This type of motion is called rotation, so the amount of time it takes an object to rotate is called a rotational period. It takes the Earth 23 hours, 56 minutes to rotate on its axis. We call the rotational period of Earth a day. Mars takes just a little longer to rotate, at 24 hours, 37 minutes. The Moon is much slower than either Earth or Mars. It takes over 655 hours for the Moon to turn just once on its axis--that's more than 27 days! Second, all the planets and moons in our solar system also move around other things.