Plutonium is much rarer in nature than uranium and is more commonly used for bombs rather than as reactor fuel. Like uranium, it comes in various isotope forms, with plutonium 239 the most commonly used. It is mixed with the much more unstable plutonium 240 to generate power.
It's my understanding that a horse's knees close around age 2- 2 1/2. My gelding JUST turned 3. A couple days ago in fact. Will a horse's knees almost certainly be closed by that age?
Thanks to specialized legs, however, a horse can lock its knees and fall asleep standing up â without falling over! A horse's fear of predators also leads it to do most of its sleeping during the day. Just because a horse can fall asleep standing up doesn't mean it never lies down, though. Sometimes horses will take naps lying down during the day. This gives them a chance to rest their legs.