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?
I'm sorry if you've run into some bad owners, but most are not what you think. We do love and care for our horses. There are many groups that retrain and place retired racehorses. Back to the original question, average age is probably somewhere in the lower 20s. While some horses do live to 30 (or more) it is not very common. The most common causes of death are colic and laminitis.