Answer:C it’s gravitational potential
Explanation:I took the test
“Star cluster” is a generic way for astronomers to refer to a group of stars that formed from the same material and are gravitationally bound for at least some period of time. There are two major types of star clusters — globular clusters and open clusters — and they are actually quite different.
<span>Nuclear reactions have two main types: fission reactions and fusion reactions. When two light nuclei are joined to create a heavier and more stable nucleus, this process is called the fusion reaction. In the fission reaction, the heavy nucleus split into two nuclei with a smaller mass number. In other words, fission is splitting of atoms although not all atoms undergo fission, only few went through normal circumstances (that is a fact). </span>
X=107 because the sides of a hexagon must add up to 720
A) 10.0g of Iron is

of Iron.
One mole of dihydrogen is required to form one mole of iron, hence you'll need

of dihydrogen.
B) Likewise : 2.50g of Iron is

of Iron, hence we'll need

of Fe2O3.