Lack of predators.
An abundance of Food.
Answer:
Human cells can readily absorb folic acid; bacteria cells cannot.
Explanation:
Bacterial cells cannot absorb folic acid and synthesize it. On the other hand, humans do not synthesize folic acid in their cells. They rather obtain it from the diet. Sulfa drugs, for example, sulfanilamide resemble p-aminobenzoate (PABA). PABA is a molecule that is used as a substrate in the synthesis of the coenzyme folic acid. The sulfa drugs serve as competitive inhibitors and compete with PABA for the catalytic site of an enzyme involved in the folic acid synthesis. This prevents the synthesis of folic acid in bacterial cells and thereby, inhibits bacterial growth.
Commensalism is the term you are looking for
Answer: B. In hypoxic tissues, in contrast to normoxic tissues, ATP is additionally consumed to transform lactate to pyruvate
Explanation:
In hypoxic tissues such as new cancerous cells, the vascular system is still underdeveloped, thus oxygen supply is reduced. To meet energy need, additional glucose is needed to convert lactate (result of anaerobic glycolysis) to pyruvate which can then go into the TCA cycle to yield energy. This phenomenon is very common in muscle tissues during exercise.
