The correct word is given as :-
behaviour, conclusion

Correct Option: D

As we can say that ,
The correct word is filled in the above given sentence :-
Unpredictable behaviour of the child could not lead the consultants to any conclusion.

The correct word is given as :-
interchange, preservation

Correct Option: B

As we can say that ,
The correct word is filled in the above given sentence :-
Our Constitution was based on the belief that the free interchange of ideas, people and cultures is essential to the preservation of a democratic society.

The correct word is given as :-
dark, frightened

Correct Option: C

As we can say that ,
The correct word is filled in the above given sentence :-
The tunnel was so dark and congested, that we became frightened.

Nuance means a subtle difference in colour, meaning, tone, etc; a shade or graduation knee jerk reaction– impulsive reaction which might not be always appropriate because here decesion/reactions are taken without much thinking. Since the issue is nuanced so it has to be studied carefully and given proper time to be analysed otherwise it would result in a loss of opportunity. All other choices are irrevelent.

Correct Option: C

Nuance means a subtle difference in colour, meaning, tone, etc; a shade or graduation knee jerk reaction– impulsive reaction which might not be always appropriate because here decesion/reactions are taken without much thinking. Since the issue is nuanced so it has to be studied carefully and given proper time to be analysed otherwise it would result in a loss of opportunity. All other choices are irrevelent.
The correct word is filled in the above given sentence :-
These issues are extremely Nuanced and any knee jerk reaction will ultimately result in a loss of opportunity for all shareholders

Expert professionals are having to train, and students supplant (replace) teachers.
The correct word is given as :-
are, supplanting

Correct Option: A

As we can say that ,
Expert professionals are having to train, and students supplant (replace) teachers.
The correct word is filled in the above given sentence :-
A growing number of these expert professionals are having to train foreigners as the students end up supplanting the teachers who have to then unhappily content with no jobs at all or new jobs with drastically reduced pay packets