Make a paragraph about the importance of homogeneous mixture to our environment and how to become better stewards for the environment.

Why are pipes bursting in the in extremely cold weather?

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.

Can someone me with 3 and 4 plz. this is for masteries test.