The correct answers from the choices are:
a. Reduce inflammation locally
b. Antagonize H1 receptors
c. May be administered orally
<span>d. Are systemically distributed
</span><span>Antihistamines are drugs that are H1 antagonists or blockers, may be administered orally, are distributed systemically, and do not directly reduce nasal congestion.</span>
Answer : The balanced reduction half-reaction is:

Explanation :
Redox reaction or Oxidation-reduction reaction : It is defined as the reaction in which the oxidation and reduction reaction takes place simultaneously.
Oxidation reaction : It is defined as the reaction in which a substance looses its electrons. In this, oxidation state of an element increases. Or we can say that in oxidation, the loss of electrons takes place.
Reduction reaction : It is defined as the reaction in which a substance gains electrons. In this, oxidation state of an element decreases. Or we can say that in reduction, the gain of electrons takes place.
The given balanced redox reaction is :

The half oxidation-reduction reactions are:
Oxidation reaction : 
Reduction reaction : 
In order to balance the electrons, we multiply the oxidation reaction by 2 and reduction reaction by 3 and then added both equation, we get the balanced redox reaction.
Oxidation reaction : 
Reduction reaction : 
The balanced redox reaction will be:

Thus, the balanced reduction half-reaction is:

Answer: The components of a pure substance are single elements or compounds instead of a mixture of compounds.
Explanation: Pure substance consits of a pure type of particle.
All elements and compounds that are considered as pure will have fixed boiling point and melting point.
Moles of hydrogen = 5.08 x 10^16
---------------------------
6.02 x 10^23
= 8.43 x 10^-8 moles.
Answer:
The statements that correctly describes pyruvate dehydrogenase includes:
- Several copies each of E 1 and E 3 surround E 2.
-A regulatory kinase and phosphatase are part of the mammalian PDH complex.
-E 2 contains three domains.
Explanation:
Pyruvate dehydrogenase is a hydrolase key enzyme in glucose metabolism which converts pyruvate to acetyl- ChoA. It also forms a complex that catalyzes an irreversible reaction that is the entry point of pyruvate into the TCA cycle. Pyruvate dehydrogenase complex contains E1, E2 and E3 enzymes that transform pyruvate, NAD+, coenzyme A into acetyl-CoA, CO2, and NADH. Also, A regulatory kinase and phosphatase are part of the mammalian PDH complex and E 2 contains three domains.