AS & A Level Marine Science (9693) — May–June 2025, Paper 31
7 questions · every question answerable online with instant point-by-point AI marking against the official mark scheme.
Start with Question 1 →Mar Menor is the largest coastal lagoon in Spain and is a major tourist destination. There are no rivers entering the lagoon, so the water there is calm, and has a maximum depth…
Answer this question and get it marked →Oysters can grow in a range of salinities from 10 parts per thousand (ppt) in estuaries to 34 ppt in sea water. Fig. 2.1 shows how the concentration of body fluids in oysters…
Answer this question and get it marked →Salmon aquaculture can take place on land and in sea cages. In both places the salmon are fed on pellets. Fig. 3.1 shows the percentage of raw materials used in salmon feed…
Answer this question and get it marked →Seahorses belong to the phylum Chordata. They are small bony fish which live in shallow sheltered waters such as seagrass beds and estuaries. They are poor swimmers and rest by…
Answer this question and get it marked →Photosynthesis takes place in chloroplasts. Explain how chloroplast structure is related to this function.
Answer this question and get it marked →Describe the different ways that carbon compounds can enter the ocean.
Answer this question and get it marked →Discuss the advantages and disadvantages of releasing adult salmon produced in a hatchery into the ocean.
Answer this question and get it marked →