Experts can i please have the answer for the 13 th question. 
Dear student,
Succinic dehydrogenase is inhibited by malonate. Malonate acts as the competitive inhibitor of the enzyme succinic dehydrogenase. Malonate has structural similarity with the substrate succinate and thus competes with succinate and binds to the active site of the enzyme succinic dehydrogenase making it inactive and therefore no enzyme activity is observed.
Regards
Succinic dehydrogenase is inhibited by malonate. Malonate acts as the competitive inhibitor of the enzyme succinic dehydrogenase. Malonate has structural similarity with the substrate succinate and thus competes with succinate and binds to the active site of the enzyme succinic dehydrogenase making it inactive and therefore no enzyme activity is observed.
Regards