Deficiency of $Vitamin \ E$ causes ...... .

$A$ liquid that is colorless,tasteless,and odorless at normal temperature is:

Vitamin $A$ was discovered by

In the liver,glucose is converted into glycogen,which is stored in the ....... .

Given below are two statements:
Statement $I$: $A$ protein is imagined as a line,the left end represented by the first amino acid ($N$-terminal) and the right end represented by the last amino acid ($C$-terminal).
Statement $II$: Adult human haemoglobin consists of $4$ subunits (two subunits of $\alpha$ type and two subunits of $\beta$ type).
In the light of the above statements,choose the correct answer from the options given below:

Which of the following is essential for living systems?