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

35 The diagram shows a food chain. maize → locusts → lizards → snakes 10 000 kJ 1000 kJ 100 kJ 10 kJ What is the efficiency of energy transfer between the maize and the lizards in this food chain? A 0.01% B 0.1% C 1% D 10%

1 marks

Answer: C

This question in 0970/21 May/June 2018

40 When nitrates enter a lake they cause rapid growth of algae on the surface of the water. This causes the following changes in the lake: 1 a decrease in the concentration of dissolved oxygen in the water 2 fish and other aquatic animals die 3 an increase in aerobic respiration by decomposers 4 producers die and decomposition increases In which order do these changes occur? A 1 → 2 → 4 → 3 B 3 → 1 → 2 → 4 C 4 → 2 → 3 → 1 D 4 → 3 → 1 → 2

1 marks

Answer: D

This question in 0970/21 May/June 2018

37 Which trophic level has the greatest amount of energy? A B C D 1 mahogany tree with → 1500 aphids → 10 small birds → 2 eagles several thousand leaves

1 marks

Answer: A

This question in 0970/22 May/June 2019

35 What is a trophic level? A a group of interconnected food chains B all of the consumers in an ecosystem C an organism’s position in a food web D the transfer of energy between organisms

1 marks

Answer: C

This question in 0970/22 Oct/Nov 2019

40 When a river is polluted by fertiliser, the following processes may occur. 1 increased aerobic respiration of decomposers 2 increased growth of producers 3 decreased oxygen concentration in the water What is the correct sequence for these processes? A 1 → 2 → 3 B 1 → 3 → 2 C 2 → 1 → 3 D 2 → 3 → 1

1 marks

Answer: C

This question in 0970/21 May/June 2020

40 When a river is polluted by fertiliser, the following processes may occur. 1 increased aerobic respiration of decomposers 2 increased growth of producers 3 decreased oxygen concentration in the water What is the correct sequence for these processes? A 1 → 2 → 3 B 1 → 3 → 2 C 2 → 1 → 3 D 2 → 3 → 1

1 marks

Answer: C

This question in 0970/22 May/June 2020

37 The diagram shows the flow of energy. 1 3 Sun grass rabbit fox Which form of energy is transferred at points 1 and 3 in the diagram? 1 3 A chemical chemical B heat light C light chemical D light heat

1 marks

Answer: C

This question in 0970/21 May/June 2021

37 Which type of energy is passed from organism to organism in a food chain? A light B chemical C heat D kinetic

1 marks

Answer: B

This question in 0970/22 May/June 2021

35 The diagram shows the flow of energy through living organisms. energy from photosynthesis energy feeding energy in the Sun in plants animals Which term should be placed in both boxes to complete the diagram? A chemical B heat C kinetic D light

1 marks

Answer: A

This question in 0970/22 Oct/Nov 2022

35 The diagram shows energy flow from the Sun, through a food chain and into the environment. Sun 1 2 plant animal animal What is the form of energy for each numbered arrow? stage 1 stage 2 A heat chemical B heat kinetic C light chemical D light kinetic

1 marks

Answer: C

This question in 0970/21 May/June 2023

36 The diagram shows a food chain. tree → insect → blue tit → hawk Which statement about a pyramid based on this food chain is correct? A Drawn as a pyramid of biomass, the hawk would have the largest bar size. B Drawn as a pyramid of energy, the tree would have the largest bar size. C Drawn as a pyramid of energy, the tree would have the smallest bar size. D Drawn as a pyramid of numbers, the hawk would have the largest bar size.

1 marks

Answer: B

This question in 0970/22 Oct/Nov 2023

37 What is the main source of energy input to biological systems? A glucose B oxygen C plants D the Sun

1 marks

Answer: D

This question in 0970/21 May/June 2024

34 The diagram shows the amount of energy in kJ m–2 yr–1 at each trophic level of a food chain. producers primary consumers secondary consumers 88 000 14 000 2000 Approximately how much energy is lost between the producers and the secondary consumers? A 0.2% B 2.0% C 84% D 98%

1 marks

Answer: D

This question in 0970/22 Oct/Nov 2024

34 Which statement about a pyramid of energy for a food chain is correct? A It shows how energy is lost at each trophic level. B It shows the energy stored at each trophic level. C It shows the input of energy from the principal source. D It shows the total energy stored within an ecosystem.

1 marks

Answer: B

This question in 0970/21 May/June 2025

35 Which row describes the energy flow into and through a food chain that starts with a plant? energy transferred energy entering between organisms a food chain in a food chain A chemical chemical B chemical heat C light chemical D light heat

1 marks

Answer: C

This question in 0970/22 May/June 2025

35 Which unit could be used for the measurements needed to construct a pyramid of energy? A kJ per g per m2 B kJ per kg per year C kJ per m2 per year D kJ per kg

1 marks

Answer: C

This question in 0970/22 Oct/Nov 2025