16. Organelles can move around the cytoplasm and perform activities that are necessary for life. Each organelle has a different job.
17. The function of the nucleus is it's the main command of the cell which means that it controls most of the cell's activities.
18. It converts heat energy and turns it to food in which the cell can eat.
20. It helps control what enters and leaves the cell.
22. Cell Wall, Chloroplasts,
Answer:
The correct answer will be option-B (purine).
Explanation:
Nucleic acid structure is made up of monomer unit called nucleotide. Each nucleotide is composed of a five-carbon sugar, a phosphate group and five types of nitrogenous bases.
The nitrogenous bases are categorized in two forms the purines (adenine and guanine ) and the pyrimidines (cytosine, thymine and uracil). The "purines" contain double rings in their structure due to which they appear larger in size than pyrimidines which are made up of single rings.
Thus, Option-B is the correct answer.