Which one of the following processes is sometimes called as necessary evil?

The apparatus used for measuring rate of transpiration is called as,

The stomata open when guard cells become,

In plants,transpiration plays an important role in,

Which one of the following forms of Co₂ has controlling influence on stomatal movement?

The stomata close in water-stressed plants due to accumulation of ABA in,

Closure of stomata of normal plants can be induced by,