Directions: In this question, a sentence has been given with some of its part in bold. To make the sentence grammatically and idiomatically correct you have to replace the bold part with the correct alternative given below. If the sentence is correct as it is, mark 'No improvement required' as your answer.
1
The planet's average surface temperature has risen about 2.0 degrees Fahrenheit since the late 19th century, a change driving largely by increased carbon dioxide and other human-made emissions into the atmosphere.
» Explain it
B
'Driving largely by' is an incorrect form of the verb here and it should be replaced by the respective phrasal verb.

'Driven by' means providing the power to keep something working, or to make something happen.

'Driven by' is the correct phrasal verb that should be used here in this context.

 
Therefore, option B is the correct answer.
 
2
By building dams across rivers, which create ponds and eventually change the rivers into wetlands, beavers help species to flourishing that would otherwise struggle.
» Explain it
A
According to grammar rule, the base form of the verb 'flourish' must be used with the infinitive 'to'. 

Ex. She likes to swim.

Options other than option A don't have the base form of the verb. Hence, they are incorrect.

Option A is the right answer.
» Explain it
E
The sentence is absolutely correct and thus needs no improvement.

Option E is hence the correct answer.
» Explain it
B
The phrase given should use the demonstrative pronoun those instead of them.

Also,

Option A is incorrect due to usage of 'whom' instead of who.

Option C is absurd and the word 'because' breaks the flow of the sentence.

Option D is incorrect as 'have been' is usually used for something that started in the past and has continued up until now.

Clearly, option B is correct.
5
Informal social control is the internalization of social norms and behavior standards that allow a person to get along in their own society.
» Explain it
E
Option A is incorrect as 'that' here is the relative pronoun for 'standards' which are in plural number. The verb that follows has to agree to this.

Option B is false due to incorrect usage of which. A general thumb rule while choosing that or which is- if the sentence doesn’t need the clause that the word in question is connecting, use which. If it does, use that. Thus, which should have been replaced with that. Plus, usage of 'among' as preposition is also ungrammatical as 'among' takes a plural noun or pronoun after it. 

Option C is incorrect as usage of present participle is absurd here in the context.

Option D is the opposite of the sentence and false.

Clearly, the sentence has no error and needs no improvement.

Hence, option E is correct.