Answer:
Biological stains are used for the medical and biological industries to aid in detection of structures within tissues. This can include the detection of abnormalities, but is not limited to that. The stains are used to define and examine cell populations within the tissues, to mark cells, or to flag proteins.
Answer:
2KClO3 》》2KCl +3O2
C+ O2》》CO2
number of C moles
Required O2 moles (According to the mole ratio )
Relevant to the first equation, find the moles the KClO3, which is used to produce that amount of O2 moles
Now you can find the mass of KClO3
I mentioned the useful steps which can guide you to get the answer.
Explanation:
The compound formed by chlorine and barium is 
as the number of valence electrons in barium is 2 and in chlorine is 1. In this compound, barium acts as a cation and chlorine acts as an anion. The formation of the compound is as shown in the image.
Since, barium is an element of Group-2 (alkaline earth metal) so the other element that has a chemical formula most and least similar to the chemical formula of the compound formed by chlorine and barium should be from Group-2 (alkaline earth metal) only which has properties somewhat like barium. So, the element is strontium.
Strontium forms a compound with formula 
in which strontium acts as a cation and chlorine acts as an anion. The formation of the compound is as shown in the image.
The answer to your question would be C. Also you put two "B"'s XD
