Most water absorption in plants takes place through

$A$ column of water within xylem vessels of tall trees does not break under its weight because of

Which of the following are objections to the root pressure theory of ascent of sap in plants?
$I$. It is not applicable to plants taller than $20 \ m$.
$II$. Ascent of sap occurs even in the absence of a root system.
$III$. Root pressure is almost zero in tall gymnosperms.
$IV$. Root pressure is the only mechanism explaining the ascent of sap.
$V$. Root pressure is not developed in actively transpiring plants.

Exudation of xylem sap at the cut end of stem is due to . . . . . . pressure.

The force of tension cohesion exceeds root pressure on a

Which one of the following is the most accepted theory of ascent of sap?