The fusion reaction in the sun is a combination of hydrogen atoms fusing to create helium. The fusion reaction in larger stars involve much heavier elements like oxygen and iron. In supernovas, often elements like gold are produced
Answer: 
Explanation:
According to the law of conservation of mass, mass can neither be created nor be destroyed. Thus the mass of products has to be equal to the mass of reactants. The number of atoms of each element has to be same on reactant and product side. Thus chemical equations are balanced.
Thus in the reactants, there are 2 atoms of hydrogen and 2 atoms of iodine .Thus there has to be 2 atoms of hydrogen and 2 atoms of iodine in the product as well. Thus a coefficient of 2 is placed in front of HI.
The balanced chemical reaction is:

It’s either the first or second one
I think it’s the first one - the outer cells of the blastocyst
If the question includes x only than it’s value would be 1
K stands for thousands
1 k = 1000
1 milli = 0.001
covert 878kg to g
878 x 1000=878000 g or (8.78^5)
convert g to mg
878000 / 0.001 =878,000,000
=8.78^8
^ or E means power of