Biology · May / June 2026 · Paper 42 · Question 1

0.45 ;

1

(as windspeed increases the rate of transpiration) increases / there is a positive correlation / AW ;

2

not a linear relationship / greater increase in (transpiration) rate at higher wind speeds / AW ;

any one from:

not all of the water (taken up by the plant) is lost through transpiration ; (named) use of water by a plant ;

any two from:

1

temperature ;

2

humidity ;

3

AVP ;; e.g.

any four from:

1

transpiration pull ;

2

water moves up the xylem ;

3

there is a column of water molecules (in the xylem) ;

4

water molecules are held together by forces of attraction between them / AW ;

5

loss of water from leaf (cells) lowers water potential at the top of the plant / in the leaf / AW ;

6

(this) pulls on / creates tension, on water molecules (in xylem) ; 7

water evaporates / water vapour moves, from the, surfaces / cell walls, of mesophyll cells OR water evaporates into air spaces in the mesophyll ;

8

loss of water (vapour) by diffusion, through stomata (out of leaf) ;