Answer:
c
Explanation:
I think that's the answer
The rungs of a DNA ladder are made up of NITROGEN BASES
This is one of the definitions that is used to define C. Work. It is a change in energies from one form to another within some time frame.
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.
Answer:
Oxygen is in group 16/VIA, which is called the chalcogens, and members of the same group have similar properties. Sulfur and selenium are the next two elements in the group, and they react with hydrogen gas (H2) in a manner similar to oxygen.
Explanation: