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9. An athlete is training for a marathon event. His heart rate and stroke volume increase significantly higher than when he is at rest.

Which one of these statements explains these changes?

Muscles start relying on energy from anaerobic respiration only.

Blood needs to transport lactic acid to the kidneys for excretion.

Blood needs to transport glucose to the liver for conversion to glycogen.

Blood needs to remove carbon dioxide through the lungs as blood pH increases.

Blood needs to transport oxygen to the lungs as they contract more strongly.

Blood needs to travel close to the skin surface to reduce body temperature by radiation.

Blood needs to transport glucose absorbed by the stomach to the rest of the body.

Blood needs to be transported to the kidneys to remove excess water.

10. Vulcanization is the process of crosslinked rubber which makes rubber has an elastic property. The structure of rubber is a tangle of polymeric chains, and if the external force is strong enough, individual chains slip past one another. Therefore causing the rubber to lose most of its elasticity.

This process was discovered by Charles Goodyear in 1839 that Sulfur (S₈) and ZnO as catalyst can be linked at double bonds between chains of natural rubber polymer.

Following the figure.

What is a type of bond of crosslinked rubber?

Covalent Network

Metallic bonding

Covalent bonding

Ionic bonding

London dispersion force

Hydrogen bonding

Dipole-dipole force

11. An elevator is supported by a cable that connects to an electric motor. The elevator of mass of 783 kg is lifted vertically through a height of 22.0 m in a time of 180 s. If the motor is connected to a constant 110 V D.C. supply and the complete lifting system is 87% efficient.

What is the current in the electric motor? (Given gravitational field strength = 10 m⋅s^–2)

1.1 A

6.7 A

7.6 A

10 A

67 A

76 A

None of them

12. ABCDEF is a regular hexagon of side. Find the shaded area in cm² ?

(√3/2)a²

(√3/4)a²

(√3/6)a²

(√3/8)a²

(√3/12)a²

((3√3)/4)a²

((3√3)/8)a²

13. Substances can be transported through different processes in both biological and non-biological systems.

Which row describes the processes correctly?

14. 8.28 grams of Lead metal sheet reacts with 1.2 M, 50 cm³ of Silver nitrate, in the Erlenmeyer flask is found Silver precipitate which has 3.24 grams and the reaction causes in the below.

Pb (s) + AgNO₃(aq) → Ag (s) + Pb(NO₃)₂(aq)

What is the method to find the limiting reagent and how many percent yields of Silver precipitate? (Ar values: Pb = 207 ; Ag = 108 ; S = 32 ; O = 16)

15. An orange light ray with wavelength of 620 nm passes from air into liquid. Its speed decreases by 25%. What is the wavelength and the color of the light beam in the liquid?

155 nm and the light is invisible

465 nm and the light is blue

465 nm and the light is orange

827 nm and the light is orange

827 nm and the light is invisible

None of them

16. To go to his school, Tony first catches a bus and then catches a boat.

The probability that the bus will be on time is 0.6.

The probability that the bus will be late is 0.4.

If the bus is on time, then the probability that he will catch the boat is 0.8.

If the bus is late, then the probability that he will catch the boat is 0.6.

Given that Tony catches the boat, what is the probability that the bus was on time?

1/3

12/25

2/5

3/5

2/3

18/25

6/7

17.The contents of the blood vary according to the current health and conditions of the body. Which one of these statements is NOT true about blood contents?

Type 1 diabetics usually have high blood sugar content as their pancreases fail to produce insulin.

ADH is released by the pituitary gland to make the kidneys retain water in the blood when experiencing thirst.

Adrenaline is released by the adrenal gland to increase blood glucose level when the body has high energy demand.

Contraceptive pills artificially raise oestrogen and progesterone levels in the blood to prevent ovulation.

Taking statins can lower blood cholesterol level to lower the risk of coronary heart disease.

Antibody level in the blood rises following vaccination as the vaccine triggers lymphocytes to produce specific antibodies.

People with kidney failures will have elevated blood urea levels if left untreated.

Neurons communicate with glands via electrical signals to make them release hormones into the blood.

18. The reaction of A + B → C has 2 steps. Following the graph between potential energy and the reaction process.

and following the statement

If the catalyst is added into the reaction, the activation energy of this reaction will be lower than c.
The energy of reaction should be A + B → C + c
S is an intermediate compound and T is a catalyst.
The stability of X and Y is higher than C.
Increasing the temperature will decrease the activation energy of this reaction.

Which of the statements is true?

None of the above

More than one statement is correct

All of the above

19.Which statement(s) below is(are) INCORRECT?

P) In a wood-fired pizza oven, the heat is transferred to the pizza only by convection.

Q) Using a curling iron to curl hair, the heat is transferred to the hair only by conduction.

R) If croissants are reheated in a microwave, most heat is transferred to the bread by radiation.

S) An object is floating in a vacuum chamber. When the rate of radiation emission is equal to the rate of radiation absorption; the object is at the same temperature as its surroundings.

P only

Q only

R only

S only

P and Q only

R and S only

None of them

All of them

20. A sample initially contains 8N and 2N atoms of radioactive isotopes X and Y, respectively. Both radioactive isotopes X and Y decay in a single stage into a stable isotope Z. If the isotopes X and Y have half-life of 15 minutes and 30 minutes, what is the ratio number of atoms of X: number of atoms of Y: number of atoms of Z in the sample an hour later?

1 : 1 : 1

2 : 1 : 7

4 : 1 : 5

4 : 2 : 6

8 : 2 : 1

1 : 1 : 18

21. Embryonic stem cells have great potential in research and therapy as they have the ability to differentiate into almost all cell types in the body. Embryonic stem cells are obtained from early embryos of mammals.

Which one of the statements is NOT true regarding the generation of a mammalian embryo and the uses of embryonic stem cells?

X chromosome in an egg cell pairs X or Y chromosome in a sperm after their nuclei fuse.

New organs can potentially be grown from the stem cells for organ transplant.

Haploid nuclei of gametes fuse together to form diploid zygote during fertilisation.

Diploid precursor cells differentiate to form haploid sperms.

Zygote undergoes multiple rounds of mitosis to form a ball of cells in the early embryo.

The embryo is destroyed during the harvest of the stem cells.

If stem cells grow and divide uncontrollably, the cells could turn cancerous.

Homologous chromosomes separate during meiosis to form egg cells.

22. Concentrated aqueous copper (II) bromide was electrolyzed. After a few minutes, the remaining electrolyte solution was tested with a pH probe at 25 °C.

The gases produced at the electrodes were collected and tested with a colorless aqueous solution of sodium iodide.

Which row in the following table best describes the observations in these tests?

	the pH of the remaining solution	test of gas from anode (positive electrode)	test of gas from cathode (negative electrode)
A.	3	no observable change	violet solid
B.	3	violet solid	no observable change
C.	7	no observable change	violet solid
D.	7	violet solid	no observable change
E.	10	no observable change	violet solid
F.	10	violet solid	no observable change

23. Ecosystems are the combination of living organisms and their non-living environment. Both living organisms and their environment are dynamic and ever-changing due to both natural and human-made causes.

Which statements are true regarding how living organisms and their environment changes over time?

Deforestation decreases the amount of carbon dioxide converted by producers into biomass.
An individual of a species evolves over time by natural selection as the environment changes.
Recombinant DNA technology can contaminate natural population with undesirable genes leading to imbalances in food webs.
The emergence of a disease can decrease the size of a population while increasing the size of another population living in the same habitat.

1 and 2 only

2 and 3 only

3 and 4 only

1 and 4 only

1,2 and 3 only

12 and 4 only

1,3 and 4 only

2,3 and 4 only

24. Beta-carotene is an orange-red natural dye that is extracted from many orange-red fruits and vegetables and Curcumin is a yellow natural dye extracted from Turmeric. Both compounds are natural dyes that do not react with each other and do not react with Methanol and Hexane.

Following the structure.

If the two natural dyes are mixed in the beaker which has the mixed solvent between Hexane and Methanol, what observation in the beaker is correct? (given density of C₆H₁₄ = 655 kg/dm³ ; density of CH₃OH = 792 kg/dm³ and the mass of two natural dyes which is mixed in solvent does not change the density of solvents)

	The observation in the beaker
A.	The mixture is separated. The orange-red is the top of the beaker and the yellow is below the beaker.
B.	The mixture is separated. The yellow is the top of the beaker and the orange-red is below the beaker.
C.	The mixture is separated. The yellow is the top of the beaker and the clear solution is below the beaker.
D.	The mixture is separated. The clear solution is the top of the beaker and the yellow is below the beaker.
E.	The mixture is separated. The orange-red is the top of the beaker and the clear solution is below the beaker.
F.	The mixture is separated. The clear solution is the top of the beaker and the orange-red is below the beaker.
G.	The mixture becomes the orange solution.
H.	None of above