Skip to content / Đến nội dung
ThichHocToan.com

PIMSO 2022 - Science - Grade 7 - National Round

Question 1

The graph below shows the monthly precipitation and average monthly temperature measured at which biome?

Question illustration
  1. Tropical rainforest
  2. Desert
  3. Grassland
  4. Tundra
  5. Deciduous forest

Question 2

The following animal was found swimming in the waters near Pandan Island in the Philippines. What is the evolutionary hallmark of this animal compared to its predecessors?

Question illustration
  1. Presence of true tissues
  2. Presence of true body cavity
  3. Acquisition of notochord
  4. Segmentation
  5. Multicellularity

Question 3

This is an electron micrograph of a human plasma cell. What is the function of the (*) indicated component?
Reference: Klein et al. Blut, 1977, 35(1), 11–9.

Question illustration
  1. Contain the genetic material of the cell
  2. Produce energy to support cellular functions
  3. Sort, pack, and transport proteins to designated sites
  4. Break down food particles and used organelles
  5. Make ribosomes which synthesize proteins

Question 4

The following images show the stages of meiosis in no particular order. At which stage is the cell haploid?

Question illustration

Editorial review: identify every haploid cell shown and explain whether the choices allow one unique answer.

Original choices:
A. Image a
B. Image b
C. Image c
D. Image d
E. All of the above

Question 5

Protozoans are one-celled eukaryotic organisms which can cause pathogenic diseases and can be transmitted through different routes of infection. Which of the following protozoans can be transmitted through the oral-fecal route?
  1. Entamoeba
  2. Plasmodium
  3. Trypanosoma
  4. Leishmania
  5. Trichomonas

Question 6

SARS-CoV-2 vaccines train the adaptive immune response of the body against the viral infection. Which of the following blood cells functions in the adaptive immune response?
Source images: Yale Histology.

Question illustration
  1. Image a
  2. Image b
  3. Image c
  4. Image d
  5. Image e

Question 7

Which of the following elements would you expect to gain an electron when forming a chemical bond?
Shown below is a Periodic Table for reference:

Question illustration

Editorial convention: use the simple main-group octet model and interpret “an electron” as exactly one electron to complete the outer shell.
  1. C
  2. N
  3. O
  4. F
  5. Ne

Question 8

Which of the following is NOT true?
  1. An element may exist with different isotopes and ionic forms
  2. Ions of the same element always has the same number of neutrons
  3. Elemental atoms having different number of electrons are different ionic forms
  4. Isotopes of an element have the same number of protons
  5. None of the above

Question 9

The table below shows the properties of different liquids A to D:
Liquid; Color; Density (g/ml); Boiling Pt (°C); Other properties
A; Blue; 1.05; 95; Hydrophobic
B; Green; 1.06; 73; Hydrophilic
C; Red; 1.21; 80; Hydrophilic
D; Yellow; 0.82; 60; Hydrophobic
Which of the following illustrates the best way to layer the liquids?

Question illustration

Editorial review: examine both density ordering and whether the liquids must remain as four separate phases.

Original choices:
A. Image a
B. Image b
C. Image c
D. Image d
E. None of the choices

Question 10

Biofuels are sources of energy from renewable sources. One example is bioethanol, which is ethanol (C2H6O) sourced from fermentation of plant products. In one experiment, 1.00 g of liquid ethanol was found to burn with 2.08 g of gaseous oxygen. Like most hydrocarbons, this combustion process produces water (H2O) and gaseous carbon dioxide. The experimental setup allowed a student to recover 100 % of the water produced from this reaction but not all of the gaseous carbon dioxide. What would be the total weight of products the student can expect from his experiment?

Editorial review: distinguish all products formed from products actually recovered; preserve the duplicated original choices.

Original choices:
A. Less than 2.08 g
B. Exactly 3.08 g
C. Less than 3.08 g
D. Exactly 3.08 g
E. Cannot be determined from the given information

Question 11

It is recommended to use 30 % solution of isopropyl alcohol to kill bacteria or viruses. A 30 g bottle was filled with enough 30 % solution until its mass was 330 g. How much alcohol is in the bottle?

Safety/editorial note: the first sentence is a historical source claim, not disinfection advice. Use 30% by mass for the arithmetic.
  1. 99 g
  2. 9 g
  3. 90 g
  4. 99.9 g
  5. None of the above

Question 12

A sample of water is contaminated with liquid methanol. What could be the best technique to purify the sample?
  1. Filtration
  2. Decantation
  3. Chromatography
  4. Dilution
  5. Distillation

Question 13

A container ship left Manila Bay at 5:00 am. The following graph shows the distance it traveled over time. When is the acceleration of the ship LOWEST?

Question illustration

Editorial correction: use the speed–time axes actually printed, not the stem’s word “distance”; assume motion along a straight path.
  1. From 5:00 am to 7:00 am
  2. From 7:00 am to 10:00 am
  3. From 10:00 am to 1:00 pm
  4. From 1:00 pm to 3:00 pm
  5. None of the above

Question 14

Complete the following sentence about light: Decreasing the _____ of light results in higher energy.

Editorial scope: compare energy per photon in vacuum.
  1. Frequency
  2. Wavelength
  3. Amplitude
  4. Velocity
  5. Focus

Question 15

The Maria Christina Falls is a 98 m waterfall in northern Mindanao in the Philippines. Aside from being known for its natural beauty, it has been harnessed for hydroelectric power.
Assuming that water from the top of the falls contains only potential energy, at what speed would any mass of water drop at the bottom of the falls? (Assume a simplistic model in which no water from the bottom recoils and affects the speed of the falling mass of water.)

Question illustration
  1. 9.8 m/s
  2. 13.9 m/s
  3. 192 m/s
  4. 30.9 m/s
  5. 43.8 m/s

Question 16

Which of the following soundwaves show the lowest pitch?

Question illustration
  1. Image a
  2. Image b
  3. Image c
  4. Image d
  5. Image e

Question 17

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 6-hour bus running at 50 km/hr from Davao city to Agora, Cagayan de Oro. Then, a ferry boat running at 27.8 km/hr from this port to Cebu would take 9 hours. What is the average speed of this trip from Davao to Cebu?
  1. 39 km/hr
  2. 30km/hr
  3. 37 km/hr
  4. 45 km/hr
  5. Cannot be determined

Question 18

Which of the following affects the total energy of an object?
  1. position
  2. mass
  3. speed
  4. mass and speed
  5. position, mass, and speed

Question 19

This desert has been considered as the world’s driest non-polar desert whose surface is said to resemble that of Mars’.
  1. Atacama
  2. Antarctica
  3. Namib
  4. Turkestan
  5. Taklamakan

Question 20

The knowledge we have today of the earth’s distant past were mostly obtained by studying the fossilized remains of different organisms. The well-preserved remains of Wooly Mammoths such as Yuka that were uncovered were preserved for thousands of years through which natural method?
  1. Permineralization
  2. Burial
  3. Molds and Cast
  4. Freezing
  5. Recrystallization