Final answer:
Thomson's experiment revealed that atoms can be divided into smaller parts known as electrons and that electrons are fundamental components of all atoms.
Step-by-step explanation:
J. J. Thomson's cathode ray tube experiment markedly altered the scientific understanding of the atom in two key ways. Firstly, it showed that atoms could be divided into smaller parts known as electrons, effectively proving that atoms were not indivisible as previously thought. This discovery is represented in option B. Secondly, the experiment indicated that these electrons were fundamental components common to all atoms, suggesting a universal aspect of atomic structure across different elements, which is captured in the phrasing of the option that states all atoms contain electrons. However, the experiment did not provide evidence that atoms combine in different proportions (option A), that all atoms of the same element are similar (option C), or that individual atoms could be destroyed (option D).