Answer:C. Creating helium from hydrogen in its core
Explanation: Stars produce energy majorly by nuclear fusion. The process of creating helium by merging hydrogen atoms to produce deuterium which in turn is converted to helium.
The right answer is CaF2
Calcium fluoride is an inorganic compound of formula CaF2. This ionic compound consisting of calcium and fluorine is naturally present in nature in the form of fluorine (also known as fluorite). It is the world's leading source of fluoride.
It is a solid insoluble in water, whose structure is cubic where each atom of calcium is adjacent to eight atoms of fluorine, and each atom of fluorine to four atoms of calcium.
