In 1869, Dmitri Mendeleev was trying to arrange the 65 known elements in a logical way. He arrived at the solution when he saw the elements arranged by atomic weight in a dream. He tried this arrangement and it worked! What is this an example of?

Heat from the sun reaches earth to a. radiation b. convection c. conduction

Which of these statements is true? a. quarks pair with leptons to form protons and neutrons. b. quarks pair with bosons to form photons. c. quarks pair with photons to form protons and neutrons. d. quarks pair with other quarks to form protons and neutrons. e. quarks pair with electrons to form protons.

Which of the following correctly describes what happens when an atomic bomb explodes? small pieces of fissionable material are joined and form a body with a mass greater than the critical mass, the relative number of neutrons escaping decreases, and a chain reaction and explosion result. large pieces of fissionable matter are brought together quickly and form a body with a mass smaller than the critical mass, the relative number of escaping neutrons increases, and a chain reaction and explosion result.