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?
My 32 year old mustang mare still looks and acts like a horse 1/4 her age!! she still all her teeth, has great muscle tone and mass, but due to arthritis in her knees, she is forced (to her way of thinking) to walk when we go out on the bridle path for exercise.