/marks>\n- **For international hardwood agreements:** Explains that agreements (such as the FSC or ITTA) restrict the import/sale of timber to only those from certified, sustainable sources M1\n- Explains that this reduces the profitability of illegal logging and incentivises governments and logging companies to practice sustainable forestry to access global markets A1","marks":4,"order":0,"markingRubric":null,"explanation":null,"options":[]}],"options":[],"explanation":null,"firstAttemptFullMarks":null},{"id":"4525c4e4-605c-495a-a5da-762908708d10","revisionId":"29efd5f1-6a94-4cc0-8b87-58ff4731411c","questionNumber":null,"questionType":"LA","specification":"In a marine kelp forest ecosystem off the coast of California, the total biomass of sea urchins (primary consumers) is significantly lower than the total biomass of the giant kelp (primary producers) upon which they feed.","difficulty":5,"difficultyBand":"medium","totalMarks":3,"sourceTitle":null,"calculatorUse":null,"parts":[{"id":"8500eea1-f4f2-4957-92bc-d12df9628517","label":null,"content":"Explain **two** biological reasons why biomass is lost between these successive trophic levels.","markscheme":"- Mentions that some parts of the giant kelp are not eaten by the sea urchins, or are indigestible and lost as waste through egestion (feces) B1\n- Mentions that biomass is lost as waste products of metabolism through excretion (such as carbon dioxide and water from respiration) B1\n- Mentions that sea urchins use biomass/glucose in respiration to release energy for movement and metabolic processes, resulting in energy/mass being lost to the surroundings as heat B1","marks":3,"order":0,"markingRubric":null,"explanation":{"methods":[{"id":"biomass_losses","label":"Trace biomass losses","steps":[{"type":"text","order":1,"title":"Explain excretion","content":"Some biomass that the sea urchin takes in is used in respiration. This produces carbon dioxide and water, which leave the sea urchin as metabolic waste through excretion, so that material cannot become new sea-urchin biomass. **This earns B1 for excretion of metabolic waste.**","highlights":[{"text":"total biomass of sea urchins (primary consumers) is significantly lower than the total biomass of the giant kelp (primary producers)","location":"specification"}]},{"type":"text","order":2,"title":"Explain heat loss","content":"The sea urchin also uses biomass in respiration to release energy for movement and other metabolic processes. Some of that energy is transferred to the surroundings as heat, so less is available for building new biomass. **This earns B1 for respiration and energy lost as heat.**","highlights":[{"text":"Explain **two** biological reasons why biomass is lost between these successive trophic levels.","location":"specification"}]}]}],"generatedAt":"2026-07-21T04:15:46.074Z","modelVersion":"gpt-5.6-terra","explanationVersion":"v3"},"options":[]}],"options":[],"explanation":null,"firstAttemptFullMarks":null}],"subjectCode":"gcse_geography__aqa","summaries":[{"id":"0367b2ce-b2cd-4fb4-832c-5fcdc746a23c","difficultyBand":"hard","calculatorUse":null,"totalMarks":6},{"id":"05d16a3d-d7a8-4435-b276-3f5fb4313504","difficultyBand":"hard","calculatorUse":null,"totalMarks":6},{"id":"09dd5477-bc92-4982-943f-de4d3730d264","difficultyBand":"medium","calculatorUse":null,"totalMarks":3},{"id":"0a734d94-8cc1-46b6-aebf-12d44a82774f","difficultyBand":"easy","calculatorUse":null,"totalMarks":1},{"id":"0b0730ec-b8a9-4bc4-bdb7-0dcf3d52ab53","difficultyBand":"medium","calculatorUse":null,"totalMarks":2},{"id":"113e6b27-ef61-429e-aade-c5e5f14e362b","difficultyBand":"easy","calculatorUse":null,"totalMarks":1},{"id":"14ef8ee7-ae7b-4dbb-ac26-eb056b30b840","difficultyBand":"easy","calculatorUse":null,"totalMarks":2},{"id":"151fabf8-6c9b-4fdd-ac60-eaba1b39087c","difficultyBand":"easy","calculatorUse":null,"totalMarks":1},{"id":"15aed21c-3c99-41f0-8243-e1da4878df8b","difficultyBand":"easy","calculatorUse":null,"totalMarks":1},{"id":"1ce1baee-a66c-4c53-8ada-088

The living world

Question 6

The living world Questions

The living world

Question 6

The living world Questions