When two hydrogen nuclei combine to form one helium nucleus, nuclear fusion has taken place. t f

This is true. That's what simply put nuclear fusion is, combining to elements in which a new element is created. That is of course much more complex, but plainly put that's what it is.

Adozen is 12, and your needing to calculate the weight of one medium egg, so i would do 21/12=1.75 per egg, and check your answer by doing 1.75 * 12= 21 : ) : ): ): ): ) i hoped i

Sorry i dont understand the question can you rephase it?