Based on the article “will the real atomic model stand up? ” why did j. j. thomson experiment with cathode ray tubes?

Astronomers discover an exoplanet (a planet of a star other than the sun) that has an orbital period of 3.87 earth years in its circular orbit around its sun, which is a star with a measured mass of 3.59 x 1030 kg. find the radius of the exoplanet's orbit.

Which one of the following research methods can show cause and effect

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