Answer: A small middle portion of the sperm contains the mitochondria. The tail of the sperm, sometimes called the flagellum, is a slender, hairlike bundle of filaments that connects to the head and middle portion. The tail gives the sperm cell movement. It whips and undulates so that the cell can travel to the egg.
<span>Killer whales are much more common in highly productive cold water areas. These include the Atlantic, the Pacific Northwest, and the higher latitudes of the Southern Ocean.</span>
It's controversial because the best source of stem cells is a human embryo (an aborted fetus).
