Answer:
that the second one surely represent the beta particle
Nitrogen N I think would be the answer
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.
Unicellular organisms...
Contain a single cell in their body
Do not contain membrane bound organelles
Use simple diffusion as a transport mechanism
All cellular processes are carried out by the single cell
Only visible under the microscope
Injury in the cell leads to the death of the organism
Asexually reproduce by binary fission
Sexually reproduce by conjugation
Lifespan is comparatively short