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?
Above: Photo of a Galvayne's groove in a 14 year old horse. When using teeth to try to determine the age of a horse older than 10 years, the Galvayne's groove is one of the indicators many horsemen will use. First appears at the gum line in horses about 10 years of age. 2  Each year, the groove will extend a little farther down the tooth. 3  It is expected to be about halfway down the tooth at 15 years of age, and all the way down (visible from top to bottom) at 20 years of age.