The graph showing the concept of activation energy of enzyme is given below. Observe the graph and choose the correct option for M and N.

Match the following:
In the following, \( [x] \) denotes the greatest integer less than or equal to \( x \). 
Choose the correct answer from the options given below:
For x < 0:
f(x) = ex + ax
For x ≥ 0:
f(x) = b(x - 1)2
Secondary growth is an increase in girth of thickness of the axis due to activity of lateral meristem. The tissues involved in secondary growth are two lateral meristems are vascular cambium and cork cambium.