Research completed by Harlow Shapley was most dependent upon what scientific tool? Please help me this is a test due today, I provided a picture.

Predict the products butane (c4h10) + oxygen —>

Explain that newton first law, second law and third law of motion?

Americium-241 undergoes fission to produce three neutrons per fission event. if a neutron-absorbing material is mixed in with this sample so that the rate of neutron production drops down to 1.8 neutrons per fission event, which will be effective at achieving a critical mass? check all that apply. remove a deflective shield surrounding the sample. remove absorbent material mixed in with the sample. compress the sample of americium-241.