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.
It's A: an animal that transfers pollen from flower to flower.
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What exactly is the question you are asking?
An electrolyte is a term used to describe a compound that can dissociate into ions as it is nothing but an ionic compound, a salt made up of a positively charged cation and negatively charged anion.
Here the correct answer is D. Since there are no hydrocarbons or any other organic compound, that do not possess partial let alone full charges, all of them can dissociate in solution to give their ions.
This allows for the solution to be able to conduct electricity.
Its a C with 4 dots, 1 on top,1 on bottom, 1 on the left and 1 on the right