Zachary has been trying to work on an essay for almost three hours, be he can't seem to focus for more than 15 or 20 minutes at a time. what should he do so that the quality of his work doesnt suffer because of poor concentration and lack of energy

Which of the following ideas did greek philosopher democritus contribute to the atomic theory? a. each object is made up of one atom, which varies in size from very small to very large. b. matter is composed of only one kind of particle, which can be easily destroyed. c. every element has a specific type of atom, which remains the same size in all forms of matter. d. all matter is composed of small particles, which combine to make larger objects.