Answer : The correct option is, (C) 6
Explanation :
Oxidation-reduction reaction : It is a reaction in which oxidation and reduction reaction occur simultaneously.
Oxidation reaction : It is the reaction in which a substance looses its electrons. In this oxidation state increases.
Reduction reaction : It is the reaction in which a substance gains electrons. In this oxidation state decreases.
The given unbalanced chemical reaction is,

Half reactions of oxidation and reduction are :
Oxidation :
......(1)
Reduction :
.......(2)
In order to balance the electrons, we multiply equation 1 by 2 and equation 2 by 3, we get:
Oxidation :
......(1)
Reduction :
.......(2)
The overall balanced chemical reaction will be:

From this reaction we conclude that the electrons are getting transferred from iron to iodine and the number of electrons transferred are 6 electrons.
Hence, the correct option is, (C) 6
Answer:
Option C= A hydrogen bond formed between a polar side chain and a hydrophobic side chain.
Explanation:
All three given options a, b and d have common mechanism to accommodate the polar amino acid.
A= A hydrogen bond forms between two polar side chains.
B= A hydrogen bond from between a polar side chain and protein back bone.
D = hydrogen bond form between polar side chains and a buried water molecules.
All these are use to accommodate the polar amino acid.
While option C is not used. which is:
A hydrogen bond formed between a polar side chain and a hydrophobic side chain.
I would say that it would be excessive rain and heat. Because, after a drought and a flood happen, standing water is home to mosquitos which carry malaria. I hope this helps!
Density = mass/volume = 80 g/10cm³ = 8 g/cm³