Transpiration — Paper 2 · IGCSE Biology (9-1) 0970

16 Petroleum jelly is waterproof and transparent. Covering the underside of the leaves of a plant with a thin layer of petroleum jelly will slow down the rate of water loss from the plant. Which statement explains this? A Plants absorb nutrients from the petroleum jelly. B Plants absorb water from the petroleum jelly. C Stomata are blocked by the petroleum jelly. D The petroleum jelly stops photosynthesis.

1 marks

Answer: C

This question in 0970/21 May/June 2018

17 The table shows the rate of water flow through a tree over a 12 hour period. rate of flow time of day / cm per hour 17:00 100 19:00 120 11:00 140 13:00 250 15:00 300 17:00 260 19:00 180 What conclusion can be drawn from the table? A Between 7:00 and 17:00 hours the rate of flow continuously increases. B The greatest increase in rate of flow in a two-hour period is between 11:00 and 13:00 hours. C Water does not flow up through a tree at night. D Water flow is affected by humidity.

1 marks

Answer: B

This question in 0970/21 May/June 2019

17 The table shows the rate of water flow through a tree over a 12 hour period. rate of flow time of day / cm per hour 17:00 100 19:00 120 11:00 140 13:00 250 15:00 300 17:00 260 19:00 180 What conclusion can be drawn from the table? A Between 7:00 and 17:00 hours the rate of flow continuously increases. B The greatest increase in rate of flow in a two-hour period is between 11:00 and 13:00 hours. C Water does not flow up through a tree at night. D Water flow is affected by humidity.

1 marks

Answer: B

This question in 0970/22 May/June 2019

15 The diagram shows an experiment to investigate transpiration. transparent plastic bag balance plant 1 plant 2 Plant 1 is not covered. Plant 2 and its pot are covered by a transparent plastic bag. The mass of each plant and its pot is measured. The masses are measured again after two hours. What is the result? A The mass of both plants decreases by the same percentage. B The mass of both plants stays the same. C The mass of plant 1 decreases more than the mass of plant 2. D The mass of plant 2 decreases more than the mass of plant 1.

1 marks

Answer: C

This question in 0970/22 Oct/Nov 2019

33 What is a feature of some xerophytes? A large air spaces in the tissues B leaves rolled up and covered with hairs C leaves with stomata on the upper surface D thin cuticle

1 marks

Answer: B

This question in 0970/22 Oct/Nov 2019

16 What will increase the rate of transpiration in a plant? A an increase in the humidity of the atmosphere surrounding the leaf B an increase in the surface area of the cell surfaces inside the leaf C a decrease in the number of stomata present on the surface of the leaf D a decrease in the temperature of the atmosphere surrounding the leaf

1 marks

Answer: B

This question in 0970/21 May/June 2020

34 Which adaptation may be present in a xerophyte? A leaves with small surface area and large numbers of stomata B little or no xylem tissue and leaves with large surface area C stomatal hairs and rolled leaves D thin or no cuticle and deep roots

1 marks

Answer: C

This question in 0970/21 May/June 2020

15 Which change increases the rate of water uptake by the roots of a plant? A decrease in evaporation of water from mesophyll cells B decrease in length of root hairs C decrease in water potential of root hair cells D decrease in water potential of soil water

1 marks

Answer: C

This question in 0970/22 May/June 2020

34 Which adaptation may be present in a xerophyte? A leaves with small surface area and large numbers of stomata B little or no xylem tissue and leaves with large surface area C stomatal hairs and rolled leaves D thin or no cuticle and deep roots

1 marks

Answer: C

This question in 0970/22 May/June 2020

34 Desert plants have evolved to survive in places where very little water is available. Which process is reduced to enable them to retain as much water as possible? A transpiration B translocation C respiration D digestion

1 marks

Answer: A

This question in 0970/22 Oct/Nov 2020

14 The graph shows daily carbon dioxide uptake and transpiration by the plant Agave americana. The plant is adapted to live in very dry conditions. 10 0.6 CO2 uptake 8 0.4 transpiration CO2 uptake 6 / g H2O / mg per dm2 per dm2 per hour 4 transpiration 0.2 per hour 2 0 0 0 4 8 12 16 20 24 time of day / hours What can be concluded from this graph? A More stomata are closed during dark periods. B More stomata are closed during light periods. C There is no carbon dioxide uptake during dark periods. D There is no water uptake during light periods.

1 marks

Answer: B

This question in 0970/21 May/June 2021

14 The graph shows daily carbon dioxide uptake and transpiration by the plant Agave americana. The plant is adapted to live in very dry conditions. 10 0.6 CO2 uptake 8 0.4 transpiration CO2 uptake 6 / g H2O / mg per dm2 per dm2 per hour 4 transpiration 0.2 per hour 2 0 0 0 4 8 12 16 20 24 time of day / hours What can be concluded from this graph? A More stomata are closed during dark periods. B More stomata are closed during light periods. C There is no carbon dioxide uptake during dark periods. D There is no water uptake during light periods.

1 marks

Answer: B

This question in 0970/22 May/June 2021

13 The diagram shows the surface view of part of the epidermis of a leaf. How many guard cells are present? A 0 B 3 C 6 D 12

1 marks

Answer: C

This question in 0970/22 Oct/Nov 2021

16 The diagram shows a newly planted seedling and the same seedling a few hours after being planted. seedling when planted seedling a few hours after planting soil What is the correct explanation for the change in the appearance of the leaves? A Transpiration is faster than water uptake by root hairs so cells have become flaccid. B Transpiration is faster than water uptake by root hairs so cells have become turgid. C Transpiration is slower than water uptake by root hairs so cells have become flaccid. D Transpiration is slower than water uptake by root hairs so cells have become turgid.

1 marks

Answer: A

This question in 0970/22 Oct/Nov 2021

33 What is an adaptive feature of xerophytes? A They do not have root hair cells. B Their leaves have a large surface area. C They have many stomata. D Their leaves have thick cuticles.

1 marks

Answer: D

This question in 0970/22 Oct/Nov 2021

16 The diagram shows a cross-section through a leaf. From which cell will most water evaporate during transpiration? A B C D

1 marks

Answer: D

This question in 0970/21 May/June 2022

16 The apparatus shown can be used to investigate the effect of temperature and humidity on the rate of transpiration. plant pot polythene bag soil 500 g balance Which set of conditions would give the highest rate of transpiration and the greatest decrease in mass? temperature humidity A cool high B cool low C warm high D warm low

1 marks

Answer: D

This question in 0970/22 May/June 2022

15 Which statement describes the effect of atmospheric humidity on the rate of transpiration? A In high humidity, the transpiration rate is high because there is slow diffusion of water vapour through stomata. B In high humidity, the transpiration rate is low because there is rapid diffusion of water vapour through stomata. C In low humidity, the transpiration rate is high because there is rapid diffusion of water vapour through stomata. D In low humidity, the transpiration rate is low because there is slow diffusion of water vapour through stomata.

1 marks

Answer: C

This question in 0970/21 May/June 2023

34 Which adaptation may be present in a xerophyte? A leaves with small surface area and large numbers of stomata B little or no xylem tissue and leaves with large surface area C stomatal hairs and rolled leaves D thin or no cuticle and deep roots

1 marks

Answer: C

This question in 0970/21 May/June 2023

15 Humidity and wind speed are two factors that affect the rate of transpiration. How do these two factors affect the concentration gradient of water molecules between the inside of the leaf and the outside atmosphere? high humidity high wind speed A lowers concentration gradient raises concentration gradient B raises concentration gradient raises concentration gradient C lowers concentration gradient lowers concentration gradient D raises concentration gradient lowers concentration gradient

1 marks

Answer: A

This question in 0970/22 May/June 2023

16 From which part of a leaf does most water evaporate during transpiration? A the cuticle B the guard cells C the spongy mesophyll cells D the xylem vessels

1 marks

Answer: C

This question in 0970/22 Oct/Nov 2023

35 Which row shows features of xerophytes that reduce water loss? areal reduced to Presence of thick cuticle chlorophyll spines A Jv x Jv x B J Jv x x Cc x Jv x v D x x Jv JV key JY = reduces water loss X = does not reduce water loss

1 marks

Answer: C

This question in 0970/22 Oct/Nov 2023

17 When is the transpiration rate of a well-watered plant highest? A on a cool, dry, windy day B on a cool, wet, windy day C on a hot, dry, windy day D on a hot, wet, windy day

1 marks

Answer: C

This question in 0970/21 May/June 2024

16 Which conditions lead to the lowest rate of transpiration in a plant? A cool and high humidity B cool and windy C warm and low humidity D warm and windy

1 marks

Answer: A

This question in 0970/22 Oct/Nov 2024

13 Which graph shows the effect of humidity in the air on the rate of transpiration in a plant? A B rate of rate of transpiration transpiration 0 100 0 100 percentage humidity percentage humidity C D rate of rate of transpiration transpiration 0 100 0 100 percentage humidity percentage humidity

1 marks

Answer: B

This question in 0970/21 May/June 2025

32 The table shows some features of leaves. Which leaf is adapted to survive in hot, dry habitats? number of thickness of surface area stomata waxy cuticle of leaf A many thick small B many thin large C few thick small D few thin large

1 marks

Answer: C

This question in 0970/21 May/June 2025

15 A student wanted to investigate the effect of humidity on transpiration. She set up two sets of apparatus with identical-sized plants of the same species. plastic bag oil water tube X tube Y The masses of the water in both tubes were measured at the start of the investigation and again after five days. The table shows the results of the investigation. mass of the water mass of the water tube in the tube in the tube at the start / g at the end / g X 40.3 34.6 Y 41.0 39.4 Which statement describes and explains these results? A Transpiration in tube Y was higher than in tube X as the plastic bag decreased the humidity. B Transpiration in tube Y was higher than in tube X as the plastic bag increased the humidity. C Transpiration in tube Y was lower than in tube X as the plastic bag decreased the humidity. D Transpiration in tube Y was lower than in tube X as the plastic bag increased the humidity.

1 marks

Answer: D

This question in 0970/22 May/June 2025

11 Which process moves water from the surfaces of the mesophyll cells into the air spaces during transpiration? A active transport B circulation C evaporation D osmosis

1 marks

Answer: C

This question in 0970/22 Oct/Nov 2025

12 The mass of water lost from a plant was investigated. The leaves of the plant were covered with a type of grease that acts as a waterproof barrier. The environmental conditions remained the same throughout the experiment. The table shows the results of the investigation. mass lost in treatment seven days / g no grease applied 12.0 grease applied only to the upper surface of every leaf 8.7 grease applied to both surfaces of every leaf 0.0 What is the mean daily rate of water loss through the upper surface of the leaves? A 0.47 g / day B 1.24 g / day C 1.71 g / day D 3.30 g / day

1 marks

Answer: A

This question in 0970/22 Oct/Nov 2025