1
1 mark
1 markThe diagram below illustrates part of the carbon cycle.
Which process is shown by the arrow labelled Y?
Photosynthesis
Feeding
Respiration
Combustion
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Energy & Feeding Relationships (CIE IGCSE Biology: Co-ordinated Sciences (Double Award))
Topic Questions
11 mark
1 markThe image shows a food web.
Which organism, from the food web, feeds on the greatest variety of organisms?
Whelks
Crabs
Limpets
Mussels
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21 mark
1 markWhich letter shows the path of the energy from the sun?
chemical energy in sugars → stored in plants → trapped in chlorophyll
trapped in chlorophyll → chemical energy in sugars → stored in plants
stored in plants → chemical energy in sugars → trapped in chlorophyll
stored in plants → trapped in chlorophyll → chemical energy in sugars
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11 mark
1 markThe graphs below show how the number of carnivores change over a period of time in a habitat.
At point X the herbivores in the habitat are removed.
Which graph correctly shows the effect of this on the number of carnivores?
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21 mark
1 markExtended Tier Only
Which statement gives the best explanation for why most food chains have no more than five trophic levels?
Because 20% of the energy is transferred at each level and after 5 levels, all the energy is used up (5 × 20% = 100%).
The numbers of organisms are insufficient because the top predator has to have a count of 1 in a pyramid of numbers.
The biomass transferred from a consumer to the next-level consumer is too little.
There is a large amount of energy loss at each level so insufficient energy can be passed up to the sixth trophic level.
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31 mark
1 markLook at the information about a food chain.
| Organism | Number | Biomass / kg |
| Oak tree | 1 | 400,000 |
| Aphids | 9,000 | 900 |
| Predatory midges | 120 | 45 |
What is the percentage biomass of the aphids transferred to the midges?
0.05 %
1.3 %
5%
0.225 %
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