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?
At the present many classify aged horses to be 16 to 18 years of age and beyond. consider horses of 20 years of age as geriatric. At the present, it has been estimated that about 10% of the U.S. horse population would be 20 years of age or older.