Brainliest for correct

each element has its own emission and absorption lines. what is the best explanation for this?

1) each element has a specific number of protons and neutrons.
2) each element has a distinct number of electrons.
3) each element has a unique set of physical characteristics.
4) each element has unique energy levels.

An example of technology is the a. addition of a side group to an organic molecule during synthesis. b. use of a new antibiotic to fight an infection. c. measurement of iron concentration in a water sample. d. study of atomic fusion reactions

Acompound has a molecular weight of 12.124 atomic mass units and the empirical formula c3h40. what is the molecular formula of the compound?

Astudent is trying to create a table that compares hypotheses, theories, and laws. hypothesis theory law do scientific researchers formulate it? yes yes yes does it explain why things happen? yes yes no yes yes yes is it used to make predictions? no yes yes which of the following questions would most likely fill the blank in the table? is it an intelligent guess? is it newly formulated? is it based on observations? has it been proved?