Answer:
your answer will be b) bonds are breaking
The answer is A-Gravity. Why? This is because B and C are examples of chemical weathering and not mechanical. Although choice D may seem viable lava intrusion is not a direct cause of mechanical weathering although lava pushing upward may help in aiding mechanical weathering it would not be considered a big enough cause, thus gravity is the correct answer.
Well, an element is a substance that cannot be decomposed into a simpler substance by chemical change, so element is the answer you are probably looking for! Hope this helps!
Answer:
an isotope has the same number of protons but a different number of neutrons than the other atoms of the same element.
