8. Question mark scheme (green pen time)
Levels
Expected responses
Level 3
A detailed and coherent explanation is given, which logically links how carbon is released from dead leaves and how carbon is taken up by a plant then used for growth (5-6 marks)
Level 2
A description of how carbon is released from dead leaves and how carbon is taken up by a plant, with attempts at relevant explanation, but linking is not clear (3-4 marks)
Level 1
Simple statements are made, but no attempt to link explanations (1-2 marks)
Level 0
Insufficient or irrelevant science. Answer not worthy of credit.
(0 marks)
Statements
(Carbon compounds in) dead leaves are broken down by microorganisms/ decomposers/bacteria/fungi
Photosynthesis uses carbon dioxide
Explanations
(microorganisms) respire
(and) release the carbon from the leaves as carbon dioxide
Plants take in the carbon dioxide released to use in photosynthesis to produce glucose
Uses of carbon in growth
Glucose produced in photosynthesis is used to make amino acids /proteins / cellulose
Which are required for the growth of new leaves

17. Describe what is happening to the world’s population and explain the consequences of this on the planet

18. Question mark scheme (green pen time)
Levels
Expected responses
Level 3
All information in answer is relevant, clear, organised and presented in a structured and coherent format. Specialist terms are used appropriately. Few, if any, errors in grammar, punctuation and spelling (5-6 marks)
Level 2
For the most part the information is relevant and presented in a structured and coherent format. Specialist terms are used for the most part appropriately. There are occasional errors in grammar, punctuation and spelling (3-4 marks)
Level 1
Answer may be simplistic. There may be limited use of specialist terms. Errors of grammar, punctuation and spelling prevent communication of the science (1-2 marks)
Level 0
Insufficient or irrelevant science. Answer not worthy of credit.
(0 marks)
human population is increasing exponentially.
result of the birth rate exceeding the death rate.
human population increases, resource use increases and therefore more pollution is created;
leading to more household waste, sewage,
sulfur dioxide from burning fossil fuels causing acid rain
carbon dioxide from burning fossil fuels causing greenhouse effect leading to global warming and climate change
Acid rain causes damage to building and statues, kills fish in lakes/streams, damages tress and soil
Global warming leads to extreme weather, melting ice-caps, rising sea-levels, flooding, drought in some areas

21. Scientists took samples of the river water at sites A, B and C.
They found larvae of three types of insect in the water. Mayfly, stonefly and caddisfly. For each type of insect they found several different species. The graph below shows the number of different species of the larvae of each three types of insect.
Describe and explain the results shown in the graph [6]

22. Question mark scheme (green pen time)
Levels
Expected responses
Level 3
All information in answer is relevant, clear, organised and presented in a structured and coherent format. Specialist terms are used appropriately. Few, if any, errors in grammar, punctuation and spelling (5-6 marks)
Level 2
For the most part the information is relevant and presented in a structured and coherent format. Specialist terms are used for the most part appropriately. There are occasional errors in grammar, punctuation and spelling (3-4 marks)
Level 1
Answer may be simplistic. There may be limited use of specialist terms. Errors of grammar, punctuation and spelling prevent communication of the science (1-2 marks)
Level 0
Insufficient or irrelevant science. Answer not worthy of credit.
(0 marks)
Site A has the biggest biodiversity/largest range of species
This decreases at Site B and site C/ the amount of new species decreases from A to C
Site A is in the forest so there will be very little pollution
Site B is next to a farm so fertilisers could be running into the water from the fields
Site C is next to a city so there will be a lot of industrial waste run off and pollution of the river
At site B the nitrates in the farm run off will increase algal growth in the water
The water plants will die and bacteria will use the oxygen left in the water for respiration – this will kill the indicator species