Home › CBSE Class 11 › Biology › Mineral Nutrition › The main DRIVING FORCE for upward water + minera…
The main DRIVING FORCE for upward water + mineral transport in tall trees is:
ARoot pressure (only at dawn typically)
BCapillary action (within thin xylem)
CActive pumping by the leaf cells
DTranspiration pull (cohesion-tension theory)
Answer & Solution
Correct answer: D. Transpiration pull (cohesion-tension theory)
TRANSPIRATION PULL drives sap up: water evaporates from leaves → tension pulls more water up through xylem (cohesion of water molecules + adhesion to xylem walls). Dixon-Joly cohesion-tension theory. Root pressure plays a minor role.
Related questions
In nodule formation, rhizobia first colonise and attach to:Which microbe makes nitrogen fixing nodules on non-legumes?Small outgrowths on legume roots are called:Which rod-shaped microbe forms nodules on legume roots?Which cyanobacterium is a free-living nitrogen fixer?Which is a free-living aerobic nitrogen fixing microbe?Nitrogen fixing microbes may be free-living or:Molybdenum is a component of nitrogenase and: