At high temperatures,enzymes become .........

$A$ - Activity of an enzyme can be affected by a change in environmental conditions.
$R$ - These factors regulate the activity of the enzyme.

Fumarase enzyme belongs to which class?

Select the incorrect statement regarding the given graph.

At temperatures below the freezing point,an enzyme is .........

The curve given below shows enzymatic activity in relation to three conditions ($pH$,temperature and substrate concentration). What do the two axes ($x$ and $y$) represent?