Are orbitals of equal energy are occupied by one electron before any single electron is occupied by a second electron . which rule applies?

In the cathode ray tube experiment, j. j. thomson passed an electric current through different gases inside a cathode ray tube in the presence of an electric field. in which two ways did this experiment change scientists’ understanding of the atom?

The reactions of photosynthesis occur in the of plant cell? a. mitochondria. b. lysosomes. c. chloroplasts. d. chlorophyll

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