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?
Best Answer: It really depends on the horse, many racers are already retired by the age of three or four. This is sad that their career ends so soon, but racing is hard and breeding is worth more money. However, some horses peak at older ages, and race as late as six years old, or even later. It is rare to see a top quality pro racers older than six. Many racers are considered to be prime racing age at three years of age, this is when all the important races are such as the Kentucky Derby.