Problem 91
How much percentage of water is used for photosynthesis? (a) \(1 \%\) (b) \(2 \%\) (c) \(3 \%\) (d) \(4 \%\)
Problem 92
Stomata helps in (a) Transpiration (b) Exchange of gases (c) Both (a) and (b) (d) None of these
Problem 93
Transpiration is affected by (a) Humidity (b) Wind speed (c) Light and temperature (d) All of these
Problem 94
The plant factor which affects the transpiration are (a) Number and distribution of stomata (b) Number of stomata open (c) Water status of plant (d) All of these
Problem 95
Transpiration driven ascent of sap depends mainly on the \(\quad\) physical properties of water. (a) Cohesion (b) Adhesion (c) Surface tension (d) All of these
Problem 96
Properties of water which provide high tensile strength (i.e., ability to resist a pulling force) are: (a) Cohesion (b) Adhesion (c) Surface tension (d) All of these
Problem 98
Sap ascends in woody stems because of the root pressure and (a) Transpiration pull (b) Capillarity (c) Molecular adhesion (d) Photosynthesis
Problem 100
The most widely accepted explanation for the ascent of sap in tree is (a) Capillarity (b) Roll of atmospheric pressure (c) Pulsating action of living cells (d) Transpiration cohesion theory of Dixon
Problem 101
The path of water from soil up to secondary xylem is (a) Soil \(\rightarrow\) Root hair cell wall \(\rightarrow\) Cortex \(\rightarrow\) Endodermis \(\rightarrow\) Pericycle \(\rightarrow\) Protoxylem \(\rightarrow\) Metaxylem (b) Metaxylem \(\rightarrow\) Protoxylem \(\rightarrow\) Cortex \(\rightarrow\) Soil \(\rightarrow\) Root hair (c) Cortex \(\rightarrow\) Root hair \(\rightarrow\) Endodermis \(\rightarrow\) Pericycle \(\rightarrow\) Protoxylem \(\rightarrow\) Metaxylem (d) Pericycle \(\rightarrow\) Soil \(\rightarrow\) Root hair \(\rightarrow\) Cortex \(\rightarrow\) Endodermis \(\rightarrow\) Protoxylem \(\rightarrow\) Metaxylem
Problem 102
A plant with well-washed roots is placed in a beaker of water diluted with red ink. The red colour travels up the stem and into the leaf veins. Which of the following should be the correct explanation of the uptake of red ink into the roots? (a) The red ink entered the root hairs by osmosis. (b) The molecules of red ink is diffused into the root hairs. (c) The membranes of the root hairs are destroyed and the red ink could enter. (d) The molecules of red ink passed from a region of low concentration to one of high concentration.
