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?
The cartilage surfaces behind the kneecap are the thickest in the entire human body and usually begin to wear out after the age of 15. Almost all people have evidence of cartilage damage on kneecap cartilage when we perform arthroscopic surgery. It is interesting to note however that while the pain from chondromalacia is the most common complaint of people between the ages of 15 and 60, these complaints usually disappear after age of 60.