What are cardinal points ? How does they affect the physiological process?

cbse
photosynthesis

#1

A factor influencing a physiological process has three principle values called cardinal points, minimum, optimum and maximum.
(a) The minimum of a factor is that value below which the physiological process cannot continue
b) Optimum value is that point where the physiological process can continue indefinitely at its highest velocity.
© Maximum value is that beyond which the process i comes to stop.