Nuclear reactors use hydrogen and they are an up and coming energy source.
There are also hydrogen fuel cells.
"Crepuscular" means active at dawn and dusk, so if you wanted to avoid coming across the Gila monster when hiking in Arizona you would want to avoid dawn and dusk.
The molecule is formed from glucose, which fits together nicely and becomes sturdy. It relates to the function of the cellulose model because it aids in strength and structural support.
Probably water. Abiotic means not living, such as sunlight or water.
B is not correct because new molecules are formed so numbers can change. D isn't correct because the color often changes, for example metallic iron and clear oxygen form red rust. The arrangement of the atoms changes, too so a isn't correct. C is cotrect
