Deep sea conditions / process of custard making - answering grammar questions

Can someone answer these grammar questions?
I attached some stuff.
For question 9, the correct answer is E.
shouldn't it be coldness not cold?
For question 7, the correct answer is E
what's wrong with answer choice D?

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  9.PNG
  
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  7.PNG
  

if you mean that a noun is required, you should know that "cold" can be either adjective and noun.


The sentence is in passive voice. "if allowed"--> "if it is allowed", so it is better to write the entire sentence in passive voice.