Is there multiple choice to this question ? But if I had to choose it would be wave
Answer: Option (b) is the correct answer.
Explanation:
A compound is defined as the substance in which different elements are chemically combined together in a fixed ratio by mass.
For example, 
is a compound and elements are present in 1:4 ratio.
A compound can be divided into its constituent or simpler substances.
On the other hand, a molecule is defined as a specie that contains same type of elements.
For example, 
is an oxygen molecule.
And, an element is defined as a substance which is made up of only one type of atoms. An element can never be broken down into its constituent particles.
For example, a piece of lithium metal will contain atoms of lithium only.
Thus, we can conclude that the statement elements are made up of one kind of atom best explains how elements can be distinguished from molecules and compounds.
Specimens taken from a patient sample usually contain a mixture of different bacteria. But sample with only one type of bacteria, are necessary to study a bacterial species accurately. Therefore, it is necessary to isolate all of the possible disease causing organisms in order to study the sample by itself. Once isolation of individual colonies is done, then these colonies can be used for identification tests. A sample of the specimen is move very fast onto an agar plate in order to physically separate the bacterial colonies.
Plasmids, they are mostly found in bacterial cells and they r the cause of antibiotic resistance in bacteries :)
Anions are negatively charged particles. The water molecule is a polar molecule, that means that, it is partly positive and partly negative. The oxygen atoms in the water molecules are more electronegative more than the hydrogen atoms and they draw the shared electron nearer to themselves than the hydrogen atoms; this make them to be slightly negatively charged while the hydrogen atom is slightly positively charged.
Therefore in solution, the anions would be attracted toward the hydrogen atom that is slightly positive while the cations will be attracted to oxygen atom that is slightly negative.
