Answer:
The correct answer is case-control study.
Explanation:
In a case-control study, two groups of the population are used, in which one group is kept as control, and the other is known as the experimental group that encounters with a specific disease or an outcome. With the help of this study, one can expose the groups to various or single outcomes.
In the given case, a study is done in which an advertisement on a ban on smoking is encouraged by the non-smokers at the alcohol sale points but not by smokers, in the process a random digit dialing method was used. This random digit dialing method is an illustration of a case-control study, in which the survey of the individuals is done regarding the ban on smoking.
arbon, as with many elements, can arrange its atoms into several different geometries, or "allotropes." In pure diamond, every carbon atom is covalently bonded to exactly 4 other carbon atoms in a very specific and energetically favorable geometry. The diamond cannot be broken or scratched unless many covalent bonds are broken, which is difficult to do. In another common allotrope, graphite, every carbon atom is covalently bonded to only 3 other carbon atoms, and the atoms are arranged in sheets that are not covalently bonded to each other. The sheets can be broken apart easily, ultimately meaning that graphite can be easily scratched. Coal is composed of particles of different allotropes of carbon, and some "amorphous carbon," which has no defined geometry in its atomic structure. Without a continuous network of covalent bonds, coal is easily scratched (i.e. it is not hard).
