Bal stands for Bronchoalveolar lavage. Bal is a process in which a bronchoscope is passed through the mouth and then into the lungs. Fluid is squirted into a part of he lung and collected for examination. Lung diseases can be found from the process of bal.
Answer:
DNA and RNA are composed of nucleotides that are linked to one another in a chain by chemical bonds, called ester bonds, between the sugar base of one nucleotide and the phosphate group of the adjacent nucleotide. The sugar is the 3' end, and the phosphate is the 5' end of each nucleiotide.
