Which of the following would probably be the most effective choice for a speech topic? a. Molecular biology b. The history of democracy c. Zoology in the Australian outback d. The migration habits of Tasmanian wombats.

i believe it is "they are not used up by reactions" as the answer to your question, text me back if this is correct because i just learned this.

in a chemical reaction, the atoms and molecules produced by the reaction are called products. no new atoms are created, and no atoms are destroyed. in a chemical reaction, reactants contact each other, bonds between atoms in the reactants are broken, and atoms rearrange and form new bonds to make the products.

for example, no new evidence will demonstrate that the earth does not orbit around the sun (heliocentric theory), or that living things are not made of cells (cell theory), that matter is not composed of atoms, or that the surface of the earth is not divided into solid plates that have moved over geological timescales .

nonmetal and metal hope this