Which of the following can you determine from mass spectrometry data?
A. Different isotopes of an element
B. Density of an element
C. Energy levels of an atom
D. Number of Particles in a sample

Select the correct answer. what was edwin hubble's contribution to the field of astronomy? a. he discovered variable stars. b. he proved that the heliocentric model accurately described our solar system. c. he found a relationship between the period luminosity and distance of stars. d. he proved that the universe is finite. e. he discovered that the universe was expanding.