Answer:
A class system is a more smooth system, caste is more of a system that changes consistently.
Explanation:
"Class system is typically more fluid than the caste system or the other types of stratification and the boundaries between classes are never clear-cut. Caste system is static whereas the class system is dynamic. ... In the caste system, individual mobility from one caste to another is impossible."
Answer:
D.both A and B
Explanation:
because if there some option,like abcd and the letter d. is both a and b that is the correct answer.
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.
