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PIMSO 2022 - Science - Grade 3 - National Round

Question 1

Mangroves are plants that are especially adapted to grow along the tropical coastal areas. In particular, mangroves have modified roots called pneumatophores, which are observed to shoot upwards from the ground. What is the function of pneumatophores?

Question illustration
  1. Habitat for fishes and other animals
  2. Release excess temperature
  3. Expel accumulated salt from seawater
  4. Exchange gasses due to waterlogged soil
  5. Added support with the changes of the tides

Question 2

The interaction between clownfish and sea anemones represents which ecological relationship?

Question illustration
  1. Commensalism
  2. Mutualism
  3. Parasitism
  4. Predation
  5. Competition

Question 3

The Philippine eagle is the apex predator in the rainforest. The following statements therefore explain how they are successful predators, except which one?

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  1. The sharp eyesight enables the eagle to see prey easily.
  2. The talons are big and powerful enough to catch and hold bigger prey.
  3. The mane-like feathers in the head alert for nearby prey.
  4. The broad wings help the eagle soar and scan the forest from above.
  5. The brown feathers help camouflage in the rainforest

Question 4

A group of paleozoologists have found dental fossils from a certain animal that existed millions of years ago. By looking at the fossil, what could they have inferred about the animal’s diet?

Question illustration
  1. Herbivore
  2. Frugivore
  3. Carnivore
  4. Insectivore
  5. Omnivore

Question 5

Trace the flow of air vibrations as it is detected by the ear and recognized as sound by the brain.
  1. Auricle → Ear canal→ Eardrum → Ossicles → Cochlea → Auditory nerve
  2. Auricle → Eardrum → Ear canal → Ossicles → Cochlea → Auditory nerve
  3. Ossicles → Ear canal → Eardrum → Auricle → Cochlea → Auditory nerve
  4. Ossicles → Eardrum → Ear canal → Auricle → Cochlea → Auditory nerve
  5. Ossicles → Eardrum → Ear canal → Cochlea → Auricle → Auditory nerve

Question 6

Some bodily fluids are designed to be the first line of defense against infectious agents. Which of the following traps the virus that causes the COVID-19 disease from further infection in the respiratory system?
  1. Blood
  2. Saliva
  3. Sebum
  4. Sweat
  5. Mucus

Question 7

Shown below are test tubes containing different materials. The particles comprising the material are illustrated. As tiny spheres. Which test tube illustrates a gas?

Question illustration
  1. Tube a in the original figure
  2. Tube b in the original figure
  3. Tube c in the original figure
  4. None of the above
  5. Cannot be determined

Question 8

You poured cold water in a glass and put it out of the balcony on a humid summer day. After some time, you noticed that the water level lowered and some drops appeared on the sides of the glass. Which of the following best explains the appearance of water droplets on the outside of the glass?

Question illustration
  1. Some of the water was absorbed by the glass
  2. Some of the water was absorbed by the glass and went to the outer side
  3. Some water evaporated
  4. Some water vapor condensed on the sides of the glass
  5. None of the above

Question 9

Consider two completely identical containers, of the same, size, shape, volume and weight. One is filled with sugar the other is filled with salt. Both were completely filled up to the brim and closed. Then, their weights were measured and the one containing salt was found to be heavier.. Which of the following properties of the matter inside the two containers is NOT different between the two?

Editorial scope: choose the equality guaranteed by the stated measurements; color is not specified.
  1. Mass
  2. Amount of material
  3. Volume
  4. Taste
  5. Color

Question 10

Which of the following is the BEST sign of a chemical change?
  1. change in composition
  2. change in color
  3. change in temperature
  4. change of phase
  5. change in shape

Question 11

Which of the following is NOT due to a physical change?
  1. making green color by mixing blue and yellow pigments
  2. heating a piece of metal on fire to make it a thin piece of sword
  3. water vapor forming clouds
  4. purification of water by distillation
  5. old statues degrading due to acid rain

Question 12

A chemical analysis procedure asks for 450 mL of water. What is the best graduated cylinders to use?

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Editorial assumption: repeated measurements are allowed; compare the number of transfers using the pictured capacities.
  1. Cylinder a in the original figure
  2. Cylinder b in the original figure
  3. Cylinder c in the original figure
  4. Cylinder d in the original figure
  5. Any of them will do

Question 13

A container ship left Manila Bay at 5:00 am. The following graph shows its speed over time. When does the ship have a non-zero acceleration?

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Editorial review: use the elapsed-time axis and explain whether any option gives every required interval.

Original choices (retained for review):
A. From 5:00 am to 7:00 am and from 9:00 am to 10:00 am
B. From 7:00 am to 9:00 am and from 10:00 am to 11:00 am
C. From 5:00 am to 1:00 pm
D. From 7:00 am to 9:00 am, from 10:00 am to 11:00 am, and from 1:00 pm to 3:00 pm
E. From 1:00 pm to 3:00 pm

Question 14

Water feels refreshing especially on hot summer days. Going to the beach, swimming pools, or water parks is a fun way to “beat the heat”. This illustrates what property of water?

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  1. Low thermal conductivity
  2. High thermal conductivity
  3. Low heat capacity
  4. High heat capacity
  5. None of the above

Question 15

Aside from the capital Manila, two other major cities in the Philippines are Cebu and Davao. It is possible to travel between these two cities by a combination of land and sea travel. One may take a bus from Davao city to Agora, Cagayan de Oro, a trip that would take 6 hours. Then, a ferry boat from this port to Cebu would take 9 hours. This would total to a distance of 540 km traveled. What is the average speed of this trip from Davao to Cebu?
  1. 60 km/hr
  2. 90 km/hr
  3. 36 km/hr
  4. 50 km/hr
  5. None of the above

Question 16

A solar lamp like the one shown below collects solar energy and stores it in a battery during the day. You can turn the lamp for light at night time. In what form of energy is the solar energy stored when the lamp is not turned on yet?

Question illustration
  1. Chemical energy
  2. Electrical energy
  3. Mechanical energy
  4. Light energy
  5. None of the above

Question 17

When making knives and swords, a smith heats a piece of metal before hitting it several times to get the desired shape. Which of the following properties of the metal changes when its temperature changes?

Editorial review: explain the property involved in forging and whether the wording makes it unique.

Original choices (retained for review):
A. Malleability
B. Hardness
C. Ductility
D. Thermal Conductivity
E. Brittleness

Question 18

What property of light determines its color?
  1. wavelength
  2. speed
  3. intensity
  4. focus
  5. luminosity

Question 19

Which of the following best describes the soil’s Horizon B layer?

Editorial scope: select the closest textbook description; the solution states its scientific limits.
  1. This layer is mostly comprised of sand and clay.
  2. This shelf covers the shore down to the deep ocean.
  3. This layer is dark in color due to the high concentration of minerals, thus nurturing plant growth.
  4. This layer mostly consists of large objects such as stones and rocks.
  5. This layer ranges down to the deepest parts of the earth’s crust.

Question 20

This type of magma existed billions of years ago during the early periods of the earth’s formation.

Editorial scope: identify the ancient-Earth magma type intended by this textbook clue, not an exclusive age test.
  1. Malfic
  2. Intermediate
  3. Rhyolitic
  4. Dacitic
  5. Ultramafic