The process of the escape of liquid from the tip of an uninjured leaf is called:

$A.$ In dry atmosphere,the relative humidity is low,so the rate of transpiration increases.
$B.$ Slow breeze promotes the rate of transpiration.
$C.$ $ABA$ promotes transpiration.
$D.$ $A$ high salt concentration in soil water increases transpiration.

Opening and closing of stomata is controlled by

If $rc$ and $rs$ respectively represent cuticular and stomatal resistances,the total resistance $(R)$ could be expressed as:

Guard cells help in

On the basis of the daily movement of stomata,Loftfield has classified the stomata into: