9693 · June 2024
Marine Science
Candidates showed a good understanding of many parts of the specification, and stronger candidates were about to use scientific terminology well. The majority of candidates answered most questions.
Source: Cambridge International
Cohort performance
Session statistics from official examination reports
No data available in official reports
Key examiner messages
Top priorities from the principal examiner before you revise
Candidates need to develop their knowledge and understanding in chemistry.
This will allow for greater detail and accuracy in responses.
Candidates would benefit from more practice in how to correctly present a word equation and in writing the formula of a molecule correctly using capital and lower case letters and superscript and subscript numbers accurately.
Question difficulty map
How candidates performed on each question in this series
Report
Examiner report
Assessment objectives
Skill and AO weighting from official examiner commentary
No data available in official reports
Method marks watchlist
Where working, steps, or method marks were commonly lost
Method marks · Report · Q1(a)(i)(c)
Most candidates gained partial or full credit on this question, with errors usually being not showing working or giving an answer to an incorrect magnitude, e.g.
Recurring mistakes across years
Themes examiners flag in multiple recent sessions for this subject
No data available in official reports
Question choice intelligence
Mean scores and popularity for optional questions (HKDSE electives)
No data available in official reports
Level exemplars
What candidate scripts at each grade level looked like
No data available in official reports
Grade & admission context
How marks relate to grade thresholds and entry standards
No data available in official reports
Deep insights
What top candidates did
Techniques and approaches examiners rewarded in this series
Cambridge International Advanced Subsidiary and Advanced Level 9693 Marine Science June 20…
Cambridge International Advanced Subsidiary and Advanced Level 9693 Marine Science June 2024 Principal Examiner Report for Teachers © 2024 MARINE SCIENCE Paper 9693/11 AS Level Theory Key messages Candidates need to develop their knowledge and understanding in chemistry. This will allow for greater detail and accuracy in responses. Candidates would benefit from more practice in how to correctly present a word equation and in writing the formula of a molecule correctly using capital and lower case letters and superscript and subscript numbers accurately. Candidates also need to ensure they read questions carefully to ensure they are using correct values in calculations. Candidates should ensure they complete all parts of each question. General comments Candidates showed a good understanding of many parts of the specification, and stronger candidates were about to use scientific terminology well. The majority of candidates answered most questions. Comments on specific questions Section A Question 1 (a) (i) More candidates were able to state proton and positive than neutron and neutral. Some candidates also gave electron and negative or electron and neutral. Candidates should know both the type of charge and the size of the charge, e.g. proton 1+, electron 1–, neutron neutral. ‘No charge’ for neutron was not precise enough. (ii) Many candidates incorrectly named sodium chloride here, but some candidates were able to name calcium carbonate. However, far fewer were able to accurately write the formula. Candidates should be aware that the formula is CaCO3, not CACO3 or CaCo3. Many candidates needed a greater understanding of how to correctly write chemical formulae. (iii) Only stronger candidates answered this correctly. Others stated that hydrogen is positive rather than saying that hydrogen has a slight positive charge, or stated that sodium is partially positive when they had correctly stated that there was a slight charge for either hydrogen or oxygen. Some candidates thought the sodium and oxygen then bonded rather than just being attracted to each other. (b) (i) Many candidates understood that water molecules slowed down or lost kinetic energy as water froze, but fewer were able to give more detail. Many candidates stated that the molecules became closer together and so density decreased, which was a contradiction. (ii) Only stronger candidates recognised that there was a conversion to do before completing the calculation (mass was given in grams, density in kg/m3). Most candidates knew the correct formula
Cambridge International Advanced Subsidiary and Advanced Level 9693 Marine Science June 20…
Cambridge International Advanced Subsidiary and Advanced Level 9693 Marine Science June 2024 Principal Examiner Report for Teachers © 2024 for the calculation, and so often gained partial credit. Some candidates over or under rounded their answers, and answers that were to 4, 5 or 6 significant figures were accepted. Candidates should apply the mathematical requirement of rounding to the same number of significant figures as given in the numbers for the calculation. Question 2 (a) (i) Many candidates gained partial credit and demonstrated an understanding of features of vertebrates in early development. However, a significant number of candidates gave responses that were too imprecise for credit. (ii) Many candidates were able to identify gill slits. Some candidates identified gill slits but they did not draw a line using a ruler or included arrowheads or simply drew a circle around the feature. The specification requires that candidates can correctly label using a straight line with no arrowheads to identify features. (b) (i) The majority of candidates correctly identified kingdom and genus and Carcharhinus melanopterus in the correct places of the table. A few candidates gave both genus and species name for the species or incorrectly placed Carcharhinus and melanopterus in the opposite places. (ii) Fewer candidates were able to give fatty acids and glycerol, with a significant number stating glucose instead of glycerol, and some giving amino acids and glucose as their answer. (iii) Stronger candidates were able to correctly state phosphates, with many other candidates stating phosphorus oxide. Slightly more candidates were able to state a use of phosphate ions correctly, often stating DNA. (c) Most candidates were able to interpret the information provided with many candidates scoring at least partial credit and many gaining full credit. Weaker candidates gave the information in the question without adding anything further to their answer. Question 3 (a) Candidates showed some understanding of the differences between weathering and erosion. Some candidates understood that one was the breakdown of rocks, and the other was removal of the sediment, but gave them in the incorrect places, and in the weathering section some candidates made statements such as ‘weathering is the erosion of rocks’. Candidates need to use these terms accurately and be aware of the difference between them. (b) Only the strongest candidates gained full credit here. More candidates mentioned salt exclusion by the roots, than air taken in by the roots, with many also mentioning lenticels. A few candidates mixed up denticles with lenticels. For the prop roots, candidates often did not mention prop or they just stated ‘prop roots’ without any further description of them. (c) (i) Many candidates mentioned global warming or deforestation as one of their responses, which would have been more relevant in (ii). (ii) Candidates gave a range of reasons why human activities have led to a reduction in mangrove cover, often global warming and deforestation. Many candidates wrote ‘pollution’ without any further detail, which was required at this level. Candidates who referred to pollution from runoff, oil pollution or water pollution gained credit. (iii) Some candidates did not round, or rounded incorrectly to give their answer to 3 significant figures. Most candidates were able to correctly identify 1200 and 1900 as being relevant numbers, but a significant number did not understand how to complete the calculation correctly. Question 4 (a) A number of candidates did not recognise that the map was slightly different to maps they may be used to seeing, in that the Pacific Ocean was in the centre. Many candidates labelled the Pacific as being to the right of North America and South America. For the Southern Ocean, candidates were often not very careful about where they labelled it with a significant number labelling it in the Indian
Cambridge International Advanced Subsidiary and Advanced Level 9693 Marine Science June 20…
Cambridge International Advanced Subsidiary and Advanced Level 9693 Marine Science June 2024 Principal Examiner Report for Teachers © 2024 Ocean or too high within the Pacific Ocean (e.g. on the coast of South America). A very small number of candidates used a label line to identify the location. (b) (i) Candidates often only focused on one aspect of the graph, either the depths or the surface temperatures, with few considering both aspects. Many candidates achieved partial credit by correctly identifying that tropical and polar regions have more stable temperatures throughout the year, or the polar regions would not reach the higher temperature that the temperate regions did, or that the tropical regions would not go as low as the temperate region. Relatively few made any comments on the thermocline depths changing but a few mentioned that the one in March was more like a polar thermocline. (ii) Many candidates knew that colder water is denser and gave the correct answer. (iii) A significant number of candidates stated that primary productivity would be different rather than stating when it would be higher and then explaining their choice. Candidates needed to consider which factors would affect productivity leading to an increase in photosynthesis. Stronger candidates sometimes mentioned nutrient availability or hours of daylight. (iv) Many candidates did not show an understanding of how to write a word equation correctly. A significant number of candidates used mixed word and symbol equations which was not acceptable and many used an equals sign rather than an arrow to show the reaction occurring. Some stronger candidates were able to correctly add sunlight and chlorophyll above and below the arrow but many candidates wrote sunlight as a reactant in the equation. Some candidates just gave carbon as a reactant rather than carbon dioxide. Some candidates needed a greater awareness of the differences between carbon, a solid, and carbon dioxide, a gas. Section B Question 5 Stronger candidates were aware of the two methods of feeding that the coral polyps may use, usually giving a good description of the symbiotic relationship with zooxanthellae, and gaining credit for capturing prey using their nematocysts. Weaker candidates usually made no mention of prey capture, but gave a good explanation of the symbiosis. Weaker candidates often spoke of the corals themselves photosynthesising, or knew there was a relationship with something else, but could not give any further details. A few candidates stated ‘zooplankton’ instead of ‘zooxanthellae’. Question 6 There were many aspects to this question that candidates could have discussed, with some candidates able to give wide ranging answers covering a variety of points. Some candidates did not mention the zones on a rocky shore, instead talking about oceanic zones and the differences in light levels. Weaker candidates demonstrated a lack of knowledge in this area, and were often unable to give the names of the different zones, or anything about how these factors changed in the different zones, or how tides may cause the different conditions within the zones. Stronger candidates were often able to suggest species that resided in the different zones, or suggested species which showed competition between themselves, or with another named species. Question 7 (a) Candidates found this a challenging question, with few commenting that the meltwater would be freshwater that could affect the salinity of the seawater. Many correctly stated that the meltwater would be colder and therefore denser, but often thought this would make the water move more slowly. A few candidates had a better understanding of the process and discussed the idea that the freshwater would float on the seawater due to its lower density. Some candidates gave a good explanation of the global conveyor belt, which gained credit, but they did not reflect on how the meltwater may influence these processes. (b) Many candidates were able to score at least partial credit here, with many stating that drought conditions would occur in Australia. Other stronger candidates explained that this was because the prevailing winds were greatly reduced or reversed, so they would no longer travel to Australia across the Pacific Ocean. Some linked this with increasing temperature and a reduced fish stock or
Cambridge International Advanced Subsidiary and Advanced Level 9693 Marine Science June 20…
Cambridge International Advanced Subsidiary and Advanced Level 9693 Marine Science June 2024 Principal Examiner Report for Teachers © 2024 MARINE SCIENCE Paper 9693/12 AS Level Theory Paper Key messages • Calculations were generally done well. When completing calculations, candidates should remember to show all the workings and should express the value to an appropriate number of significant figures. An important skill that candidates should practise is the conversion of units in calculation questions. Question 1(a)(ii) was an example where this skill was particularly beneficial. • A skill that candidates should practise is drawing and labelling of diagrams. All straight lines should be drawn with a ruler and care should be taken over accuracy of any labelling of lines and diagrams drawn. Some candidates did not gain the full credit available due to inaccurate drawing. Questions where this was particularly important were Questions 4(b)(i) and 4(c). • It is important to understand the difference between the command words in terms of response required. The terms ‘describe’, ‘explain’ and ‘state’ require different responses. Candidates should know the difference between these terms and the requirements of each. The difference in the responses required by the command words ‘describe’ and ‘explain’ were particularly important for Questions 2(c) and 4(b)(ii). General comments There was a high standard of scientific knowledge and understanding seen with many candidates providing detailed and accurate responses. There were very few questions where candidates did not offer any response, with most candidates attempting all questions on the paper. Many candidates had a broad knowledge of the syllabus, but it was evident that some areas were better known than others. For longer prose question in Section B, it may be beneficial for candidates to plan out their answers on the blank pages to organise their thoughts before attempting the question. Very occasionally, candidates did not include all the information necessary to answer the question completely and planning out their responses may have aided them in answering each question fully. Comments on specific questions Question 1 (a) (i) Candidates were generally able to identify the core and the mantle. A common error was that candidates did not separate the continental crust and oceanic crust and instead labelled one of these the crust and the other an incorrect label, such as the lithosphere or the asthenosphere. Occasionally some candidates tried to separate the core into inner and outer core, then labelled the oceanic crust as the mantle and the continental crust as the crust. (ii) Most candidates calculated this correctly with workings clearly shown. Some candidates did not pay attention to the units and did not convert their value from m to km. (b) (i) The question asked for how continents provided evidence for continental drift, not just general evidence for continental drift. This led to some candidates describing other evidence, for example the spreading of the seafloor or carbon dating, which did not gain credit. However, correct answers relating to evidence from continents were frequently seen.
Cambridge International Advanced Subsidiary and Advanced Level 9693 Marine Science June 20…
Cambridge International Advanced Subsidiary and Advanced Level 9693 Marine Science June 2024 Principal Examiner Report for Teachers © 2024 (ii) Most candidates were able to identify the direction of movement of the plates. (iii) Most candidates gave the correct response of divergent. (iv) Very occasionally there were some unclear responses that referred to too much pressure or lack of light preventing any life at the bottom of the sea. However, most candidates were able to suggest the formation of new rock or seafloor as the reason for the lack of fossils. Question 2 (a) The majority of candidates could identify examples of the different types of weathering. Candidates should be reminded to draw straight lines with a ruler. Occasionally candidates drew lines to more than one box. Physical weathering was sometimes linked with transport of rocks. (b) It appeared that some candidates confused weathering and erosion, giving the answers of physical, chemical and organic. Some candidates gave different examples of water erosion. (c) For this question, there were many unclear descriptions and not many explanations. Many candidates referred to organisms fastening onto rock with no mention of muscular foot. Many talked about wave action and not desiccation and did not link this to the close-fitting shell. This question required two separate points; a description of the feature and then how it adapts it for the environment. Candidates often gave only partially complete explanations. Question 3 (a) This question was generally answered well. A common error was to confuse the pelvic with the anal fin or pectoral fin. (b) Candidates were generally able to match the group with the example from the blue shark. Occasionally the domain was given as Animalia and the phylum sometimes given as Eukarya. (c)(i) Calculations were done well and workings shown but often the value of 60 per cent rather than 40 per cent was given. (ii) The question asked for possible reasons for the decrease in export of dried shark fins. Many candidates gave several reasons for the decrease in shark population, which was not what question asked for, although this was one factor. The strongest responses included a variety of suggestions including reasons relating to legislation, catch effort and demand. (d) Some candidates tried to answer this with no reference to sunlight. Another issue was quoting incorrect distances for both zones. Candidates seemed to be more familiar with the epipelagic than the mesopelagic zone. A few candidates described the mesopelagic zone as having no light, which did not gain credit. Question 4 (a) Some candidates tried to describe the different types of plankton. Candidates should be reminded to use scientifically correct language. Several candidates described plankton as being small instead of microscopic. Many also referred to plankton’s mobility rather than the more correct term of motility. (b) (i) Candidates were generally able to draw an accurate pyramid of biomass. Sometimes the pyramids were drawn in order of size and not trophic level. Occasionally the pyramids were drawn as an actual pyramid rather than rectangular boxes. (ii) Some candidates did not take their explanations far enough. Many talked about an increase in biomass rather than an explanation in terms of increased photosynthesis and reproduction, increasing population size and consumption. Candidates needed to explain the reason for the biomass increase or decrease. The strongest responses referred to photosynthesis and linked this to an increase in population and therefore biomass resulting in a larger food source for the copepods and so an increase in copepod population size.
Cambridge International Advanced Subsidiary and Advanced Level 9693 Marine Science June 20…
Cambridge International Advanced Subsidiary and Advanced Level 9693 Marine Science June 2024 Principal Examiner Report for Teachers © 2024 (c) Most candidates were able to complete the food chain. Candidates should be reminded to use a ruler when drawing diagrams and to use the stimulus material as a guide to the expected look of the diagram. Some candidates tried to add another box for cucumber flesh instead of realising this would be the same organism as the sea cucumber. Some did not include an arrow going from sea cucumber to copepods. Candidates needed to draw the additions to the food web in the same style by placing the organisms in boxes with ruled straight lines for the arrows and the arrows touching the boxes. Question 5 (a) There were some excellent responses seen, with many candidates laying out their work logically and with relevant detail. Some responses did not explain fully how the alignment of the Earth, Sun and Moon affected the strength of the gravitational pull on the water on Earth. Few candidates gave an initial explanation about how the Moon has a greater gravitational pull as it is closer to the Earth. Descriptions of resulting spring and neap tides were generally excellent. (b) Very occasionally candidates repeated the information for (a). However, many candidates were able to give reasonable explanations and did not just list the factors that affected tide height. Many candidates were able to give several different factors and a relevant explanation for each. Occasionally candidates showed a lack of detail in their responses and referred to, for example, onshore winds affecting tide height, without giving further detail as to how onshore winds affect tide height. Question 6 (a) There were some excellent responses seen. Some candidates concentrated only on the description of the contents of sea water and did not describe the chemical properties enabling water to dissolve salt and other substances. Candidates who did describe the chemical properties of water, generally used scientifically correct terminology, referring to the polar nature of water and how this enables water to be a solvent. A common omission from many candidates was mention of the role of dissolved nutrients such as glucose in sea water. (b) It was evident that some candidates had a lack of understanding about pH. Many knew about the effect of increase of atmospheric carbon dioxide and the resulting dissolution leading to a decrease in pH of sea water. The effect of a change in pH on coral reefs was often described in an unclear manner and was lacking in appropriate detail. Many candidates could describe coral bleaching, but fewer were able to explain the effect in terms of the calcium carbonate skeleton dissolving or the reduction in ability of coral to take up calcium carbonate.
Command word playbook
How to match each command word to the expected response style
No data available in official reports
Time traps
Sections where candidates spent disproportionate time relative to marks
No data available in official reports
Syllabus traceability
Topics linked to questions and mark weighting in this session
No data available in official reports
MCQ trap analytics
Commonly chosen wrong options from examiner commentary
No data available in official reports
Topic heatmap across years
Mark concentration by topic and exam year for this subject
No data available in official reports
Difficulty trend
How session difficulty has shifted across recent years
No data available in official reports
Paper comparison
Marks and duration breakdown across papers in this session
No data available in official reports
Marks you can still earn
Where valid approaches outside the mark scheme may still gain credit
No data available in official reports
Practise what examiners flagged
Target weak topics from this report inside the Revui app
Self-diagnostic checklist
Key actions before you sit this paper — copy and tick off as you revise
- 1Message
Candidates need to develop their knowledge and understanding in chemistry.
- 2Message
This will allow for greater detail and accuracy in responses.
- 3Message
Candidates would benefit from more practice in how to correctly present a word equation and in writing the formula of a molecule correctly using capital and lower case letters and superscript and subscript numbers accurately.
- 4Method
Most candidates gained partial or full credit on this question, with errors usually being not showing working or giving an answer to an incorrect magnitude, e.g
- 5Strength
Cambridge International Advanced Subsidiary and Advanced Level 9693 Marine Science June 20…: Cambridge International Advanced Subsidiary and Advanced Level 9693 Marine Science June 2024 Princip
- 6Strength
Cambridge International Advanced Subsidiary and Advanced Level 9693 Marine Science June 20…: Cambridge International Advanced Subsidiary and Advanced Level 9693 Marine Science June 2024 Princip
- 7Strength
Cambridge International Advanced Subsidiary and Advanced Level 9693 Marine Science June 20…: Cambridge International Advanced Subsidiary and Advanced Level 9693 Marine Science June 2024 Princip
Teacher briefing pack
One-page session summary for tutors and classroom review
June 2024 2024
Marine Science
Cambridge International Advanced Subsidiary and Advanced Level 9693 Marine Science June 2024 Principal Examiner Report for Teachers © 2024 MARINE SCIENCE Paper 9693/11 AS Level Theory Key messages Candidates need to develop their knowledge and understanding in chemistry. This wil
Candidates need to develop their knowledge and understanding in chemistry.
This will allow for greater detail and accuracy in responses.
Candidates would benefit from more practice in how to correctly present a word equation and in writing the formula of a molecule correctly using capital and lower case letters and superscript and subscript numbers accurately.
Examiner insights
General comments
- •Candidates showed a good understanding of many parts of the specification, and stronger candidates were about to use scientific terminology well.
- •The majority of candidates answered most questions.