Until the 1500s, doctors thought diseases were caused spontaneously. Scientists
began proposing that diseases were caused by
seed-like entities that could be passed among
people. After the invention of the microscope,
doctors came to know that many diseases were
actually caused by microscopic living organisms
like bacteria. What does this suggest about the
nature of scientific knowledge?-

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.