AS & A Level Marine Science (9693) — May–June 2025, Paper 21
5 questions · every question answerable online with instant point-by-point AI marking against the official mark scheme.
Start with Question 1 →Blue crabs are crustaceans. Fig. 1.1 shows a blue crab — a photograph of a crab viewed from above, showing the broad, oval carapace (upper shell), two large claws (chelipeds),…
Answer this question and get it marked →Nitrate ions (NO₃⁻) are a source of nitrogen for marine producers such as seagrass. Define the term ion.
Answer this question and get it marked →Hydrothermal vents occur close to plate boundaries. State the type of plate boundary where ocean floor spreading occurs.
Answer this question and get it marked →Fig. 4.1 shows a Southern flounder, a species of fish that lives and reproduces in estuaries — a photograph showing a flatfish with mottled brown colouring, lying flat. Scientists…
Answer this question and get it marked →Some copepods are parasites of marine fish. Describe the meaning of the term parasitism.
Answer this question and get it marked →