How did Robert proved experimentally that all bodies fall in vacuum with same acceleration?

How did Griffiths and Avery show experimentally that DNA is the hereditary material?

A body of 2 kg is suspended on a spring balance hung vertically in a lift . If the lift is falling downward under acceleration due to gravity g then what will be the reading of the balance ? If going upward with the same acceleration then ?

Two bodies of masses, m_A and m_B , are thrown up simultaneously. With reference to this situation, which of the given statement(s) about these bodies is/are correct? I. Both bodies fall towards the earth with same acceleration. Il. The body with heavier mass falls with more acceleration. III. The acceleration of the bodies in this case is directly proportional to the mass.

State Ohm's law ? How can it be verified experimentally ? Does it hold good under all conditions ? Comment.