Answer:
The correct answer is option c. "Tetracycline must be discontinued before beginning the isotretinoin".
Explanation:
Isotretinoin is a medication used to treat cases of severe acne, having dramatic positive effects since the patients start the treatment. However, the use isotretinoin should be monitored by a doctor because it is hard to process and could cause renal side effects. In this case, the patient must discontinue its treatment with tetracycline before start using isotretinoin.
The correct answer is B. Oxygen.
Oxygen, as a part of the atmosphere, also participates in UV protection, besides being necessary for breathing.
C. nucleic acids (consisting of genes which encode for specific proteins to be synthetized)
While cellular respiration releases carbon dioxide into the environment, photosynthesis pulls carbon dioxide out of the atmosphere.