Human Biology

Human Biology

Read carefully 1 Check that the answer sheet provided is for Human Biology Higher (Section A). 2 For this section of the examination you must use an HB pencil, and where necessary, an eraser. 3 Check that the answer sheet you have been given has your name, date of birth, SCN (Scottish Candidate Number) and Centre Name printed on it. Do not change any of these details. 4 If any of this information is wrong, tell the Invigilator immediately. 5 If this information is correct, print your name and seat number in the boxes provided. 6 The answer to each question is either A, B, C or D. Decide what your answer is, then, using your pencil, put a horizontal line in the space provided (see sample question below). 7 There is only one correct answer to each question. 8 Any rough working should be done on the question paper or the rough working sheet, not on your answer sheet. 9 At the end of the examination, put the answer sheet for Section A inside the front cover of this answer book. Sample Question The digestive enzyme pepsin is most active in the A B C stomach mouth duodenum

D pancreas. The correct answer is A—stomach. horizontal line (see below). The answer A has been clearly marked in pencil with a

A

B

C

D

Changing an answer If you decide to change your answer, carefully erase your first answer and, using your pencil, fill in the answer you want. The answer below has been changed to D.

A

B

C

D

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SECTION A All questions in this section should be attempted. Answers should be given on the separate answer sheet provided.
1. The diagram below shows an enzyme-catalysed reaction taking place in the presence of an inhibitor. 4. The following information refers to protein synthesis. tRNA anticodon amino acid carried by tRNA Histidine (his) Alanine (ala) Arginine (arg) Tyrosine (tyr) Methionine (met) Threonine (thr)

P

R

T S

GUG CGU GCA AUG

Q
Which line in the table below identifies correctly the molecules in the reaction? Inhibitor A B C D P Q R R Substrate R P P Q Product S S T T

UAC UGU

What order of amino acids would be synthesised from the base sequence of DNA shown? Base sequence of DNA C G T tyr met tyr tyr T A C his his his thr G T G

2. The following diagram shows a branched metabolic pathway. product inhibition

A B C D

arg ala ala arg

Q P L N M O R S
A Which reaction would tend to occur if both Q and S are present in the cell in high concentrations? A B C D L R O L M S P N 6. Carrier molecules involved in the process of active transport are made of A B C D protein carbohydrate lipid phospholipid. B C D Cell organelle Mitochondrion Ribosome Lysosome Nucleolus Function Anaerobic respiration Release of ATP Synthesis of enzymes Synthesis of RNA 5. In which of the following is the cell organelle listed correctly with its function?

3. A fragment of DNA was found to have 120 guanine bases and 60 adenine bases. What is the total number of sugar molecules in this fragment? A B C D 60 90 180 360 Page three

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7. An investigation was carried out into the uptake of sodium ions by animal cells. The graph shows the rates of sodium ion uptake and breakdown of glucose at different concentrations of oxygen. 160 ) 40 Glucose breakdown (units per minute) (

10. The transmission of a gene for deafness is shown in the family tree below. Key Affected male Unaffected male Affected female Unaffected female

120 Sodium ion uptake (units per minute) (

30

80

20

40

10 ) 0 0 1 2 3 4 Oxygen concentration (%) 5

This condition is controlled by an allele which is A B C D dominant and sex-linked recessive and sex-linked dominant and not sex-linked recessive and not sex-linked.

0

Calculate the number of units of sodium ions that are taken up over a 5 minute period when the concentration of oxygen in solution is 2%. A B C D 80 100 400 500

11. The examination of a karyotype would not detect A B C D phenylketonuria Down’s syndrome the sex of the fetus evidence of non-disjunction.

8. Which of the following statements about viruses is true? A B C D Viral protein directs the synthesis of new viruses. New viruses are assembled outside the host cell. Viral protein is injected into the host cell. Viral DNA directs the synthesis of new viruses.

12. A woman with blood group AB has a child to a man with blood group O. What are the possible phenotypes of the child? A B C D A or B AB only AB or O AB, A or B

9. What is the significance of chiasma formation? A B C D It results in the halving of the chromosome number. It results in the pairing of homologous chromosomes. It permits gene exchange homologous chromosomes. between

It results in the independent assortment of chromosomes.

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13. Cystic fibrosis is an inherited condition caused by a recessive allele. The diagram below is a family tree showing affected individuals. unaffected male affected male unaffected female affected female

16. The table below contains information about four semen samples. Semen sample A Number of sperm in sample (millions/cm3) Active sperm (percent) Abnormal sperm (percent) 40 50 30 B 30 60 65 C 20 75 10 D 60 40 70

1

2
Which semen sample has the highest number of active sperm per cm3?

3

4

5

6
17. Which of the following describes correctly the exchange of materials between maternal and fetal circulations? Glucose A B C D into fetus by active transport into fetus by active transport into fetus by pinocytosis into fetus by diffusion Antibodies into fetus by active transport into fetus by pinocytosis into fetus by active transport into mother by pinocytosis

Which two individuals in this family tree must be heterozygous for the cystic fibrosis gene? A B C D 3 and 5 4 and 6 1 and 2 2 and 6

14. The diagram below shows the influence of the pituitary gland on testosterone production.

Pituitary gland Hormone X produced Testes stimulated Testosterone produced
What is hormone X? A B C D Luteinising hormone Follicle stimulating hormone Oestrogen Progesterone [Turn over 18. The diffusion pathway of carbon dioxide within body tissues is A B C D plasma lymph tissue fluid tissue fluid cell cytoplasm cell cytoplasm plasma

cell cytoplasm tissue fluid

tissue fluid lymph

plasma.

15. From which structure in the female reproductive system does a corpus luteum develop? A B C D Endometrium Graafian follicle Fertilised ovum Unfertilised ovum Page five

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19. The graph below shows changes in arterial blood pressure. 150 Blood pressure (mm Hg) 125 100

21. Which of the following statements refers correctly to the cardiac cycle? A B C During systole the atria followed by the ventricles. contract

During systole the ventricles contract followed by the atria. During diastole the atria followed by the ventricles. contract

75 50 25 0 0 0.5 1 1.5 Time in seconds The shape of the graph is due to A B C D the action of the heart muscle the action of the diaphragm the closing of the valves in the veins C muscular contraction of the arteries. A B D

During diastole the ventricles contract followed by the atria.

22. Which line in the table below correctly describes the conditions under which the affinity of haemoglobin for oxygen is highest? Oxygen tension high high low low Temperature (ºC) 40 37 37 40

D 20. An ECG trace is shown below.

R

23. Which of the following is triggered by the hypothalamus in response to an increase in the temperature of the body? A Contraction of the hair erector muscles and vasodilation of the skin arterioles Contraction of the hair erector muscles and vasoconstriction of the skin arterioles Relaxation of the hair erector muscles and vasodilation of the skin arterioles Relaxation of the hair erector muscles and vasoconstriction of the skin arterioles

0.5 mV B P T Q S 0.3 sec What is the person’s heart rate? A B C D 100 beats per minute 120 beats per minute 150 beats per minute 200 beats per minute C D

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24. The graph below shows the rate of sweating of an individual in different environmental conditions. individual enters individual enters warm area cold area

25. The diagram below shows the main parts of the brain as seen in vertical section.

Y Z W

4
Volume of sweat produced (cm3 per min)

3

X

2

Which line in the table below correctly identifies the functions of two areas of the brain? Communication between hemispheres A W X W Z Reasoning X Y Y W

1

0
0 10 20 Time (mins) How long after entering the warm area did it take for the volume of sweat production to increase by 100%? A B C D 8 minutes 13 minutes 20 minutes 23 minutes [Turn over 30 40 B C D

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26. The diagram below shows a test on a man who had a damaged corpus callosum. This meant that he could no longer transfer information between his right and left cerebral hemispheres. barrier to restrict field of vision

27. Which of the following statements about diverging neural pathways is correct? A B C D They accelerate the transmission of sensory impulses. They suppress the transmission of sensory impulses. They decrease the degree of fine motor control. They increase the degree of fine motor control.

snow

ball

28. Which of the following describes the change in an individual’s behaviour where the presence of others causes the individual to show less restraint and become more impulsive? A B left cerebral hemisphere right cerebral hemisphere C D Social facilitation Shaping Generalisation Deindividuation

Some of the functions of each hemisphere are described in the table below.

29. Which of the following identifies correctly a process in the nitrogen cycle? A B C D Nitrifying nitrogen. bacteria trap atmospheric

Left cerebral hemisphere processes information from right eye controls language production

Right cerebral hemisphere processes information from left eye controls spatial task co-ordination

Nitrifying bacteria convert ammonium compounds to nitrates. Nitrogen-fixing bacteria convert nitrates to atmospheric nitrogen. Denitrifying bacteria convert ammonia to nitrates.

The man was asked to look straight ahead and then the words “snow” and “ball” were flashed briefly on the screen as shown. What would the man say that he had just seen? A B C D Ball Snow Snowball Nothing

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30. The diagrams below contain information about the population of Britain.

AGE Males 75+ 70–74 65–69 60–64 55–59 50–54 45–49 40–44 35–39 30–34 25–29 20–24 15–19 10–14 5–9 0–4 Females

600 Annual death rate from coronary heart disease per 100 000 people

Male Female

400

200

0 55–64 55–64 Age (years)

2.5 2 1.5 1 0.5 0

0 0.5 1 1.5 2 2.5

Population size (millions) How many British men between 55 and 64 years of age die from coronary heart disease annually? A B C D 400 6000 12 000 24 000

Candidates are reminded that the answer sheet MUST be returned INSIDE the front cover of this answer booklet.

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Marks SECTION B All questions in this section should be attempted. All answers must be written clearly and legibly in ink. 1. The diagram below represents stages in the production of human sperm.

A

mother cell

1st division B

2nd division

C

sperm

(a) Name the type of cell division that produces sex cells. 1 (b) State the number of chromosomes which would be present in the cells labelled A, B and C. A: B: C: 1

(c) Compare the appearance of the chromosomes in cell B and cell C.

1 (d) Name the two processes which increase variation during the 1st division of the sperm mother cell. 1 2 (e) State the location of sperm production in the testes. 1 1

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Marks 2. The diagram below shows some of the reactions which occur during aerobic respiration.

glucose Stage A pyruvic acid

acetyl CoA

4-carbon compound

Stage B

citric acid

reduced molecule R

molecule R water

Stage C molecule S

(a) Complete the table by naming stages A, B and C and indicating their exact location within the cell.

Stage A B C

Name

Location

3 (b) A glucose molecule contains 6 carbon atoms. How many carbon atoms are found in the following molecules? Pyruvic acid Citric acid 1

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Marks 2. (continued) (c) Complete the following sentences by naming molecules R and S and describing their function with respect to stage C. R is and its function is

. S is and its function is

. (d) Under normal circumstances carbohydrate is the main respiratory substrate. In each of the following extreme situations, state the alternative respiratory substrate and explain why the body has to use it.

2

Situation

Respiratory substrate

Explanation

Prolonged starvation

Towards the end of a marathon race

2

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Marks 3. The diagram below shows blood from a person who has been infected by bacteria. These bacteria have triggered an immune response involving proteins P and Q. The diagram is not drawn to scale. protein Q T-lymphocyte bacteria

surface protein P macrophage

red blood cell

cell R

(a)

(i)

Identify proteins P and Q. P Q 1

(ii)

Cell R produced protein Q. Name this type of cell. 1

(iii)

Describe the role of the following cells in combating infection. (A) T-lymphocyte 1 (B) Macrophage 1

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Marks 3. (continued) (b) Complete the following sentences by underlining one option from each pair of options shown in bold. (i) Immunity gained after contracting a bacterial infection is an example of active / passive immunity that is naturally / artificially acquired. Immunity gained from the injection of a tetanus vaccine is an example of active / passive immunity that is naturally / artificially acquired. 1

(ii)

1

(c) What happens during an autoimmune response?

1

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4.

Lactose is the main sugar found in milk. Lactose is broken down by lactase, an enzyme which is made by cells lining the small intestine. The glucose and galactose molecules produced are then absorbed into the bloodstream. lactase

Marks

lactose

glucose + galactose

A student carried out an investigation to compare the lactose content of human milk and cow milk. He set up a test tube containing human milk and lactase solution. Every 30 seconds samples were taken and the glucose concentration measured. Then he repeated the procedure with cow milk. His experimental setup is shown in Figure 1. His results are shown in the table below. Concentration of glucose (%) Human milk 0 0.28 0.54 0.80 1.04 1.10 1.10 Cow milk 0 0.28 0.46 0.54 0.58 0.58 0.58 human milk and lactase cow milk and lactase Figure 1

Time (min) 0 0.5 1.0 1.5 2.0 2.5 3.0

(a) Lactose is a disaccharide sugar. Explain how the information above supports this statement.

1 (b) One variable that must be kept constant in this investigation is pH. List two other variables which would have to be kept constant. 1 2 1

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Marks 4. (continued) (c) Construct a line graph to show all the data in the table. (Additional graph paper, if required, can be found on Page thirty-six.)

3 (d) What conclusion can be drawn from this investigation?

1 (e) Suggest a reason why the rate of glucose production is not constant throughout the investigation.

1 (f) How could the student improve the reliability of his results?

1

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Marks 4. (continued) (g) Some people who have problems digesting lactose are said to be lactose intolerant. They cannot produce the enzyme lactase. (i) What general phrase describes an inherited disorder in which the absence of an enzyme prevents a chemical reaction from happening? 1 (ii) A test can be carried out for lactose intolerance. The individual being tested does not eat for twelve hours and then drinks a liquid that contains lactose. The individual rests for the next two hours during which their blood glucose level is measured at regular intervals. What results would be expected if the individual is lactose intolerant?

1

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Marks 5. The diagram below shows a section of a woman’s breast shortly after she has given birth.

secretory gland duct

rib

nipple

(a)

(i)

Name the hormone that stimulates the secretory glands to start producing milk. 1

(ii)

The cells lining the secretory glands are particularly rich in ribosomes. Suggest a reason for this.

1 (b) Fluid is not usually released from the breast until the baby suckles. (i) What name is given to the first fluid that the baby receives from the breast? 1 (ii) Describe one way in which this first fluid differs from the breast milk produced a few days later.

1 (iii) Suckling and crying are examples of non-verbal communication used by a baby. Why is non-verbal communication important to both the mother and baby?

1
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Marks 6. The flow diagram below summarises what happens in the body after a meal of fish and chips.

Digestion of fish and chips in the stomach and small intestine

Absorption of the products of digestion through the walls of the small intestine

Metabolism of some absorbed substances by the liver

Transport of some products of metabolism around the body in the bloodstream (a) Explain how bile salts aid the digestion of the fish and chips.

1 (b) The products of fat digestion are fatty acids and glycerol. Describe the route taken by these products as they move from the small intestine to the bloodstream.

2

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Marks 6. (continued) (c) During the absorption and metabolism of this meal, samples of blood from the hepatic portal vein and the hepatic vein were tested for glucose and urea. Complete each row of the table below, using the words Higher and Lower, to compare the concentration of each substance in the two blood vessels.

Blood vessel Substance Glucose Urea 2 (d) State one feature of veins which helps to maintain blood flow. Hepatic portal vein Hepatic vein

1 (e) Drugs and alcohol pass into the bloodstream through the digestive system. The liver converts these harmful substances into harmless products. What term describes this action of the liver? 1

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Marks 7. A long distance runner took part in some laboratory tests using a treadmill. She was asked to use the treadmill at a setting of 4 km/h for three minutes during which her pulse rate was monitored. At the end of this time a blood sample was taken which was tested for lactic acid concentration. The procedure was then repeated a number of times at faster speeds. The results of the tests are shown in the graph below.

blood lactic acid concentration 10

pulse rate 200

8

180

6 Blood lactic acid concentration (mMol/l) 4

160 Pulse rate (beats/min) 140

2

120

0 4 6 8 10 12 14 16 18 Running speed (km/h) (a) (i) What was the runner’s pulse rate when she was running at 6 km/h?

100

1 (ii) State the concentration of lactic acid in the runner’s blood when her pulse rate was 172 beats/min. mMol/l (iii) Predict what the runner’s blood lactic acid concentration would be if she ran at 18 km/h for three minutes. Blood lactic acid concentration mMol/l 1 1

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Marks 7. (continued) (b) A build-up of lactic acid in muscles leads to fatigue. (i) Explain why lactic acid builds up in the muscles as running speeds increase.

2 (ii) Distance runners often monitor their pulse rate while they are training. Suggest how this runner could use a pulse rate monitor and the information from the graph to allow her to run for long periods of time without developing muscle fatigue.

2

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Marks 8. Two men (P and R) were being tested for diabetes mellitus, a condition which results in failure to control blood glucose concentration. After fasting overnight, they were given a large glucose drink. Their blood glucose concentration was measured immediately (0 hours) and then every hour for five hours. The results of the tests are shown in the table below.

Time after drinking glucose (hours) 0 Blood glucose concentration of P (mg/100 ml) Blood glucose concentration of R (mg/100 ml) 145 1 210 2 190 3 180 4 170 5 160

90

125

90

85

90

90

(a) It was concluded that P had diabetes and R did not. (i) State two ways in which the test results indicate that P has diabetes. 1 2 (ii) Name the hormone responsible for the change in the blood glucose concentration of R (A) (B) between 1 and 2 hours between 3 and 4 hours. 1 1

(b) Diabetes insipidus can be caused by a lack of ADH in the body. (i) Which organ of the body releases ADH? 1 (ii) State an effect that failure to produce ADH would have on the body.

1

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Marks 9. The diagram below shows a synapse between two nerve cells in the brain and a magnified view of a receptor called NMDA.

cell X

vesicle containing a neurotransmitter magnified view

NMDA receptor

synapse

cell Y

(a)

(i)

Describe how the neurotransmitter in the vesicle reaches cell Y.

2 (ii) The diagram above shows a single neural pathway. Explain how a converging neural pathway would be more likely to generate an impulse in nerve cell Y.

2 (b) Many factors can lead to memory loss. (i) One of these factors is a reduction in the number of NMDA receptors. Which part of the brain contains nerve cells rich in NMDA receptors? 1 (ii) Another factor is the decreased production of acetylcholine. Name the condition which results from the loss of acetylcholine-producing cells in the brain. 1
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Marks 10. A study was carried out to compare the influence of genetics with that of the environment on the development of two behavioural conditions, A and B. Several hundred pairs of children, from the same families, took part in the study. Some pairs were monozygotic twins, some pairs were dizygotic twins and some pairs were adopted and unrelated. In each pair, one of the children had one of the behavioural conditions and investigators observed whether or not the other child shared the condition. Results of the study are shown in the bar graph below. 90 80 70 60 Pairs of children 50 sharing the condition 40 (%) 30 20 10 0 A B Behavioural condition (a) Explain why it was important that monozygotic twins were chosen for this study. monozygotic twins

dizygotic twins

adopted children

2 (b) Use the graph to explain whether conditions A and B are more likely to be caused by genetic or environmental factors. (i) Likely cause of condition A Explanation 1 (ii) Likely cause of condition B Explanation 1
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Marks 11. The bar graph shows population changes in Scotland for different age groups between 1991 and 2000.

1200 1000 Number of people (× 1000) 800 600 400 200 0 0–14 15–29 30–44 45–59 60–74 75 and over Age group (a) Suggest a reason for the population change in those aged 75 and over.

1991 2000

1 (b) Describe two ways in which the data for the year 2000 would be different if it were taken from a developing country with a similar population size to Scotland. 1

2 1 (c) Describe two ways in which the information in the graph could be used by authorities to plan for the future. 1

2 1

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Marks 12. An investigation was carried out into the influence of adults on the behaviour of young children. Some groups of children watched a recording of either a man or a woman being physically and verbally aggressive to a large plastic clown. Other groups of children watched either a man or a woman behaving in a non-aggressive manner towards the clown. Each child was then placed in a room on their own with the clown. The number of aggressive acts they committed over a five minute period was counted. The figures in the table below show the average number of aggressive acts that the children committed while in the room.

Average number of aggressive acts committed by the children Gender of children Boys Girls Aggressive man observed 18.7 4.4 Aggressive woman observed 7.9 9.2 Non-aggressive man observed 1.0 0.2 Non-aggressive woman observed 0.6 0.8

(a)

(i)

Which adult/child combination resulted in the least aggression? 1

(ii)

Calculate the percentage increase in aggressive acts committed by boys when they observe an aggressive man rather than a non-aggressive man. Space for calculation

% (iii) State a conclusion that can be drawn from these results regarding the gender of the aggressive adult.

1

1 (b) The children are observing and then repeating the acts of adults. What form of learning are they using? 1 (c) Suggest a control that could have also been used in this investigation.

1
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13.

The graph below shows the application rates of nitrogen and phosphorus to crops in an area of Scotland between 1986 and 2006. nitrogen 130 50 phosphorus 120 45 Phosphorus application 40 rate (kg/ha) 35

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Marks

Nitrogen application 110 rate (kg/ha) 100

90 1986

1990

1994 Year

1998

2002

30 2006

(a) Describe one similarity and one difference in the data for nitrogen and phosphorus application rate between 1986 and 2006. Similarity

Difference 2 (b) Express, as a simple whole number ratio, the application rate of nitrogen compared to phosphorus in 1986. Space for calculation : nitrogen phosphorus (c) In recent years, there has been a decrease in the use of nitrogen and phosphorus on farms in Scotland. (i) Suggest one way in which this decrease might benefit the environment. 1

1 (ii) Suggest one way in which this decrease might disadvantage farmers.

1
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Marks 14. Glaciers are large masses of ice on mountains and in cold regions of the world. The graph below shows the average change in glacier thickness around the world between 1955 and 2005. +2 0 –2 –4 Change in glacier –6 thickness (m) –8 –10 –12 –14

5

0

5

0

5

0

5

0

5

0 200

195

196

196

197

197

198

Year (a) (i) Calculate the average yearly decrease in glacier thickness between 1955 and 2005. Space for calculation

198

199

199

200
m/year

5

1

(ii)

One consequence of this decrease in glacier thickness is rising sea levels. Describe one effect of rising sea levels and subsequent flooding on coastal communities around the world.

1

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Marks 14. (continued) (b) Many people believe that the change in glacier thickness is caused by global warming. (i) Name two gases that contribute to global warming. 1 (ii) 2 1

Give two reasons why one of these gases is increasing in the atmosphere. Gas Reason 1

Reason 2 1

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Marks SECTION C Both questions in this section should be attempted. Note that each question contains a choice. Questions 1 and 2 should be attempted on the blank pages which follow. Supplementary sheets, if required, may be obtained from the Invigilator. Labelled diagrams may be used where appropriate. 1. Answer either A or B. A. Discuss memory under the following headings: (i) short-term memory; (ii) the transfer of information between short and long-term memory. OR B. Discuss how man has attempted to increase food supply under the following headings: (i) chemical use; (ii) genetic improvement; (iii) land use. 4 3 3 (10) 5 5 (10)

In question 2, ONE mark is available for coherence and ONE mark is available for relevance.

2.

Answer either A or B. A. OR B. Discuss the conducting system of the heart and how it is controlled. (10) Discuss the biological basis of contraception. (10)

 

 
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