A radioactive element is an element which is subject to spontaneous degeneration of its nucleus followed by the emission of alpha, beta and gamma particles. All elements with atomic numbers greater than 83 are radioactive.
The given phrases that describe radioactive elements are-
They have a consistent number of particles
- the particles are alpha, beta and gamma particles.
They have a half-life that determines their rate of decay.
Explanation for other options:
Not all elements occur in nature. Radioactive decay rates may not be constant as the decay happens when a radioactive substance emits a particle. It is not possible to predict exactly when a given atom of a substance will emit a particular particle. When the radioactive element release energy and particles, it decays.
Hey there..
If I'm correct the guidelines are: reuse, reduce and recycle.
Hope it helps :)
Answer:
Alveoli are tiny, balloon-shaped air sacs. Their job is to move oxygen and carbon dioxide (CO2) molecules into and out of your bloodstream.
Explanation:
The limitation is that she can't test is on humans for ethical reasons. In order to test this, theoretically, she would need to ask some women to use this cosmetic and compare their fetuses to the fetuses of women who didn't. But this is not likely to be approved by the ethical committee, as causing damage to a fetus is not ethical.
