Answer: The circulatory system.
Explanation: The circulatory system, which is part of the "cardiovascular" system, is one of the eleven organ systems of the human body. Its main function is to transport nutrients to cells and wastes from cells (Figure 3.4. 1). This system consists of the heart, blood, and blood vessels.
Answer: The element Na (Sodium) is getting oxidized and Hydrogen is getting reduced.
Explanation:
Oxidation reactions are the reactions in which addition of oxygen takes place.
Reduction reactions are the reactions in which loss of oxygen takes place.
For a given reaction:

Sodium is getting oxidized because there is an addition of reaction with that element.
Hydrogen is getting reduced because there is a removal of oxygen with that element.
the false statements are a, and e (not sure about e but think a is false)
Answer:
TABLE OF CONJUGATE ACID-BASE PAIRS Acid BaseK a (25oC) HClO 4ClO 4 – H 2 SO 4HSO 4 – HCl Cl– HNO 3NO 3 – H 3 O +H 2 O H 2 CrO 4HCrO 4 –1.8 x 10–1
Explanation: