The answer is D because the box b's force to the left is not being cancelled out and box d's force is trying to be cancelled out, but he has more force going up then down so he is moving up
B I think, it has layers that protects the cells nucleus
Answer:
a process that involves rearrangement of the molecular or ionic structure of a substance, as distinct from a change in physical form or a nuclear reaction.
Or
Chemical reaction, a process in which one or more substances, the reactants, are converted to one or more different substances, the products. ... A chemical reaction rearranges the constituent atoms of the reactants to create different substances as products.
