Answer:
A) Sample B has more calcium carbonate molecules
Explanation:
M = Molar mass of calcium carbonate = 100.0869 g/mol
= Avogadro's number = 
For the 4.12 g sample
Moles of a substance is given by

Number of molecules is given by

For the 19.37 g sample

Number of molecules is given by


So, sample B has more calcium carbonate molecules.
The ratio of the elements of carbon, oxygen, calcium atoms, ions, has to be same in both the samples otherwise the samples cannot be considered as calcium carbonate. Same is applicable for impurities. If there are impurites then the sample cannot be considered as calcium carbonate.
I remember learning this last y’all i jus don’t remember it might be A or C
Answer: The person lived for 80.66 years.
Explanation:
Heart beat of the person = 73 beat /min
Number of total heart beats = 
Life span of the person : 
1 year =525600 mins
Life span = 
The person lived for 80.66 years.
Explanation:
option option B is the correct answer of given statement helium-4(He)=2