81. In guard cells when sugar is converted into starch, the stomatal pore
A. Closed completely
B. Opens partially
C. Opens fully
D. Remains unchanged
Answer : Option A
82. Water will be absorbed by root hairs when the externael medium is
83. Root hairs occur in the zone of
A. Cell division
B. Cell elongation
C. Cell maturation
D. Mature cells
Answer : Option C
84. Path of water movement from soil to xylem is
A. Meta xylem - protoxylem - cortex - soil - roothair
B. Cortex - root hair - endodermis - pericycle - protoxylem - meta xylem
C. Soil - root hair - cortex - endodermis - pericycle - protoxylem - meta xylem
D. Pericycle - soil - root hair - cortex endodermis - protoxylem metaxylem
Answer : Option C
85. Water in plants is transported by or ascent of sap takes place through
86. Water rises in the stem due to
A. Cohesion and transpiration pull
B. Turgor pressure
C. Osmotic pressure
D. Root pressure (negative)
Answer : Option C
87. The principal pathway of water translocation in angiospermis is
A. Sieve cells
B. Sieve tube elements
C. Xylem vessel system
D. Xylem and phloem
Answer : Option B
88. Which contributes most to the transport of water from soil to the leaves of a tree ?
A. Root pressure
B. Cohesion of water and transpiration pull
C. Capillary rise of water inside xylem
D. Hydrolysis of ATP
Answer : Option D
89. Cohesive force of water is due to
90. Diffusion of water through selectively permeable membrane is