IMPOSSIONABLE

By using the letters of given word 'CORRESPONDING'.
'DISCERN' is the only word which can be formed

By using the letters of the given word 'MEASUREMENT' we can form the word MASTER.

From the given word, 'MEDICO' is the only word can be formed.

From letters O, I, T, N only one meaningful word 'INTO' can be formed and last letter of this word is O.

Given sequence is
1, 11, 21, 1211, 111221, ........
Now, analyse the terms -
1^st term = 1
2^nd term - It describes the 1^st term term that is has "one" "one" or 11
3^rd term it describes the 2^nd term that it has "two" "one" or 21
4^th term It describes the 3^rd term that it has "one" "2" and "one" "1" or 1211
5^th term It describes the 4^th term that it has "one" "1" "one" "2" and "two" "1" or 111221
Hence the 6 term would be - "Three" "1", "two" "2" and "one" "1" or 312211

'TALENT' word cannot be formed using the letters of the given word CONSTITUTIONAL because letter E is not present in the given word CONSTITUTIONAL .

The word 'SECURE' cannot be formed from 'COURAGEOUS' because E letter is used twice in 'Secure' but letter 'E' is given only one time in word 'COURAGEOUS'.

From the given word, 'TUTOR' is the only word which can be formed.

From the given word, 'CHANGE' is the only word which cannot be form due to the absence of letter 'G' in MERCHANDISE

From the given word PORTFOLIO ,
'PORTICO' is the only word which cannot be formed due to absence of letter 'C'.