AS & A Level Marine Science (9693) — May–June 2025, Paper 33
7 questions · every question answerable online with instant point-by-point AI marking against the official mark scheme.
Start with Question 1 →Snow crabs (Chionoecetes opilio) live in cold waters at depths of up to 1800 m. They feed on detritus and other invertebrates. They are commercially important but their numbers…
Answer this question and get it marked →Sea cucumbers are echinoderms. They are a food delicacy in Asia and are harvested from the wild. In some countries, harvesting adult sea cucumbers has been banned to try to…
Answer this question and get it marked →Phytoplankton blooms occur naturally in some aquaculture ponds and can affect the concentration of dissolved oxygen. Aquaculture ponds can be extensive (low stock density with no…
Answer this question and get it marked →Atlantic salmon (Salmo salar) are euryhaline. They are born in freshwater rivers, migrate to the sea, and then return to freshwater to breed. Fig. 4.1 shows osmoregulation in an…
Answer this question and get it marked →Hydrothermal vents are found on the ocean floor at depths of approximately 2000 m. Describe the conditions at hydrothermal vents AND the ecosystems that hydrothermal vents support.
Answer this question and get it marked →The European green crab (Carcinus maenas) is one of the most invasive species in the world's oceans. Originally from the north-east Atlantic and Baltic Sea, it has spread across…
Answer this question and get it marked →Mitochondria are organelles found in eukaryotic cells. Describe the structure AND function of a mitochondrion.
Answer this question and get it marked →