Which statement best describes the amount of catalyst that remains at the end of a reaction?

more catalyst is present at the end than at the beginning of the reaction.
less catalyst is present at the end than at the beginning of the reaction.
the amount of catalyst is the same at the end as at the beginning of the reaction.
the catalyst is consumed by the reaction, so none remains at the end of the reaction.

Why is the structure of molecule important to its function?

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.

How does blood clotting prevent the entry of pathogens through cuts and wounds? answer asap,, this is due tomorrow. will mark as brainliest or whatever you call it : )