Stable elements are those which have atleast one isotope with no tendency to "decay", i.e., change into anotherelement.
Yes it could change the park if you remove a population from the national park
The biceps and triceps muscles work together to allow you to bend and straighten your elbow. When you want to bend your elbow, your biceps muscle contracts (Figure below), and, at the same time, the triceps muscle relaxes. The biceps is the flexor, and the triceps is the extensor of your elbow joint.
