Sound waves require a medium to travel through, such as a solid, liquid or gas because
a) waves cannot move through a vacuum.
b) sound only works within certain pressures.
c) waves only work within certain temperatures.
d) sound is molecules bumping into one another.

Can someone me with 1 to 4 plz. fast

Astudent is asked to identify and element that is pale yellow brittle solid and does not conduct electricity. at which location in this periodic table would the element most likely be found?

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.