Which phrase describes one characteristic of radioactive elements? are produced in a laboratory
O decay at a constant rate
O have a consistent number of particles
release energy and particles to maintain radioactivity

B) decay at a constant rate

Explanation:

Over their lifetime, the radioactive elements tend to have constant rate of decay. This is seen in chemistry in Kinetics, where we see that radioactive elements follow first order kinetics where the rate at which they decay is constant (no matter what concentration we have)