11. R.Q. is highest when respiratory substance is
(a) Fat
(b) Maleic acid
(c) Glucose
(d) Protein
12. An indispensible role in energy metabolism is
(a) Sodium
(b) Phosphorus
(c) Calcium
(d) Potassium

Dear student,                                                                                                                                
​Please find below the solution to the asked query    

11. R.Q. is highest when respiratory substance is an organic acid. Since maleic acid is an organic acid, the respiratory quotient for maleic acid is highest.
Hence, option (b) is correct.

12. An indispensable role in energy metabolism is played by phosphorous. It causes hydrolysis of pyrophosphate and is required for phosphyrylation reactions that are essential for energy metabolism.
Hence, option (b) is correct.

Hope this information will clear your doubts about the topic.    Regards