Which of the following is an example of enzymes belonging to the class of ligases?

Enzymes as they exist inside the cell are

When is the enzyme released from the enzyme-substrate complex in its original form?

Given below are the statements regarding enzymes. Choose the correct statements.
$i$. All enzymes are proteinaceous.
$ii$. Enzyme becomes more active at the temperature of $60^{\circ}C$ to $70^{\circ}C$.
$iii$. Enzymes have one or two active sites where substrate binds with the enzyme.
$iv$. Any increase or decrease in specific $pH$,enzyme activity is always enhanced.
$v$. Enzymes remain active to catalyze again after completion of first reaction.

Enzymes are basically or all enzymes contain:

Which of the following is a competitive inhibitor of succinic dehydrogenase?