Explain why a sidewalk has built-in cracks every few feet?

Stage in which a star’s outer layers have started to cool and grow outward?

What can be found in the ionosphere

Afusion reaction takes place between carbon and another element. neutrons are released, and a different element is formed. the different element is a) lighter than helium.b)heavier than helium.c)the same weight as helium.d)dependent on the element that reacted with carbon.