1. NAT REVIEWER IN SCIENCE & HEALTH 6
Name: ________________________________ Gr./Section:___________________________
I. Direction: Encircle the letter of the correct answer.
1. It is the complete trip of the blood from the heart to all parts of the body and
back to the heart.
a. Digestion
b. Circulation
c. Respiration
d. Secretion
1. What happens to the blood when it reaches the lungs?
a. The blood becomes pure and clean.
b. The blood becomes oxygenated in the lungs.
c. The blood becomes deoxygenated in the lungs.
d. The blood flows continuously to the lungs.
1. What makes the blood flow through the blood tubes?
a. The blood becomes oxygenated in the lungs.
b. The blood does the circular movement.
c. The heart pumps blood to different parts of the body.
d. The heart has two ventricles for pumping blood.
Below is a diagram of the heart. Use this illustration for item 4-5.
1. Which part of the heart that contracts and pumps the blood containing rich oxygen to
all parts of the body?
a. 2
b. 3
c. 6
d. 7
1. Which part of the heart that contracts and forces the blood out of the heart to the
lungs?
a. 7
b. 6
c. 3
d. 2
1. Which of the following controls our body activities?
a. Nerves
b. Spinal cord
c. Brain
d. Backbone
1. Which of the following carries/carry messages to and from the brain?
a. Nerves
b. Spinal cord
c. Vertebrae
d. Backbone
1. Why can you hear sounds?
a. The nerves that are sensitive to sound carry the message to the brain.
b. The nerves that are sensitive to light carry the message to the brain.
c. The outer ear collects sounds.
d. The sounds are loud enough.
1. The action that happens without our thinking about it is _____.
a. Receive action b. Reflex action c. Retract action d. Reverse action

2. 1. What is the function of the spinal cord?
a. Responsible for man’s ability to learn habits and develop skills.
b. Enables us to think, learn, remember, and be aware of many things
around us.
c. Enables the sensory and motor information to pass between the brain
and the parts of the body.
d. Carry impulses from sense receptors to the central nervous system.
1. The part of the nervous system responsible for organizing our muscle messages so we
can move smoothly.
a. Brain stem
b. Cerebellum
c. Cerebrum
d. Hypothalamus
1. This is the ability to face things as they are, to be happy and cheerful most of the
time, to get along with others and to work in helpful ways.
a. Good mental health
b. Friendly status
c. Positive action
d. Negative attitude
Below is an illustration of a food chain in a land community. Use this illustration in answering
item 13-15
1. To what order of consumer does the frog belong in the food chain?
a. First-order consumer
b. Second-order consumer
c. Third-order consumer
d. Fourth-order consumer
1. Which is an herbivore in the food chain?
a. Bacteria
b. Grasshopper
c. Frog
d. Snake
1. Which is not true about the illustration?
a. The process of eating and being eaten involves a series of organisms.
b. A food chain starts with the producer.
c. A food chain ends with the decomposer.
d. The amount of food increases as the number of consumers increases.
1. Which of the following shows a food chain in the pond community?
a. Algae Small fish turtle
b. Corn plant pig man
c. Water plant small fish sword fish
d. Kangkong man
Below is an illustration of a food web. Use this for item 17.
1. What does a food
a. It shows a complex
b. It shows a fixed
c. It shows the growth of decomposers in the cycle.
d. It shows a continuous series of eating activities.
Below is an illustration of the Oxygen-Carbon Dioxide Cycle. Refer to this illustration
for item 18.

3. 1. Which is not true about the illustration above?
a. X is carbon dioxide used by plants while Y is oxygen used by animals.
b. Man and other animals eat foods which combine with oxygen and release
carbon dioxide.
c. Y is carbon dioxide used by plants while X is oxygen used by animals.
d. It shows the give and take relationship between plants and animals.
1. What is oxygen-carbon dioxide cycle?
a. Plants give off and oxygen to the air as a waste product and animals take in oxygen
with the air they breathe in.
b. The chemical energy of food is taken from the plant.
c. It is the transformation of energy in the bodies of plant eaters.
d. Water and minerals enter the plants through the rrots.
1. Why will the plants have an endless supply of minerals from the soil?
a. The soil contains the minerals needed by plants.
b. The roots of plants are in the soil.
c. The substances of plants and animals go back to the soil through
the decaying process.
d. The roots get minerals from the soil.
1. An environment where both living and non-living things exists and interact with one
another.
a. Food chain
b. Food web
c. Ecosystem
d. Atmosphere
1. These are microorganisms that change complex substances to simplier
components.
a. Producers
b. Decomposers
c. Consumers
d. Predators
1. What kind of energy is involved when ice melts?
a. Light energy
b. Chemical energy
c. Heat energy
d. Nuclear energy
1. When the electric fan is on and revolving, what energy changes are shown?
a. Mechanical to heat
b. Heat to electrical
c. Electrical to mechanical
d. Chemical to mechanical
1. What is the change of one form of energy into another?
a. Law of conservation of energy
b. Transformation of energy
c. Energy transfer
d. Potential energy
1. _______________ is the abnormal rise in the earth’s temperature.
a. Global warming c. Acid rain
b. Greenhouse effect d. Ozone hole

4. 1. Why can a bus travel faster in going down a mountain than in going up?
a. Because of gravity
b. Because of air pressure
c. Because of friction
d. Because of the speed of wind.
1. Which of the following explains the law of inertia?
a. If no force acts on an object that is moving, it will continue moving at the
same speed and direction.
b. An object accelerates because of a force that acts on it.
c. For every action, there is an equal and opposite reaction.
d. A force causes the object to move in circular motion.
1. What does a speed limit of 80 km/ hr mean?
a. The minimum speed a car can travel is 80 km/hr.
b. The maximum speed a car can travel is 80 km/hr.
c. A car can travel more than 80 km/hr.
d. A car is not allowed to have a speed less than 80 km/hr.
1. Which of the following explains the second law of motion?
a. If the object is stopped, it will remain still unless a force will make it move.
b. The larger the mass of an object, the greater force needed to accelerate it.
c. For every action there is an equal and opposite reaction.
d. A force causes the object to move in circular motion.
1. Some scientists believe that the universe started as a hot ball of materials which
exploded and became stars and galaxies. What is this theory?
a. Steady-state theory
b. Big bang Theory
c. Pulsating theory
d. B and C
1. What forms/form part of a constellation?
a. Group of stars
b. Connecting lines between dots
c. Stars
d. Big Dipper
1. Which theory explains that the earth is made up of major plates that once joined
like a
jigsaw Puzzle.
a. Plate tectonic theory
b. Continental Drift theory
c. Theory of isostasy
d. Theory of evolution
1. It is believed to be made of solid materials. It has a diameter of about 2, 560 to 2, 880
kilometers.
a. Outer core
b. Inner core
c. Mantle
d. Crust
1. This is a liquid rock where the crustal plates are said to float over.
a. Asthenosphere
b. Magma
c. Earth
d. Mantle
1. This is where the Philippines is located.
a. Eurasian plate
b. Pacific plate
c. Antarctic plate
d. Crustal plate.

5. 1. What can you infer about the universe from your knowledge about the sizes and
distances of stars constellations and galaxies?
a. The universe is very young.
b. The universe is very cold.
c. The universe is very vast.
d. The universe is very changeable.
1. What will happen when strong wind blows toward a man who is spraying
pesticide on his plants?
a. The pesticide will be wasted.
b. The pesticide spray might fall on him.
c. The pesticide will not come out of the container.
d. The pesticide will not be useful.
1. Which of the following illustrations shows the molecules in a liquid?
a. c.
b. d.
1. Chemical spray is harmful to the environment. Why?
a. It affects the clouds.
b. It pollutes the rivers and oceans.
c. It destroys the ozone layer.
d. It destroys our clothes.
1. Why is the core of the earth very hot?
a. Due to pressure
b. Due to hot gases.
c. Due to the “ring of fire”
d. Due to crustal plates.
1. The layer of the earth that lies below the crust that extends uo to about 2, 900
kilometers.
a. Crust
b. Mantle
c. Core
d. Trench
1. Which of the following shows that a volcano has been formed?
a. When there is an earthquake.
b. When there is tsunami that brings big waves.
c. When magma under the earth’s crust escapes through a vent
d. When there is a very big explosion that produces a loud sound.
1. In which part of the earth’s interior is magma found?
a. Inner core
b. Outer core
c. Mantle
d. Crust
1. Why can planet earth support life?
a. It has an atmosphere.
b. It has soil where green plants grow.
c. It has enough sunlight.
d. All of the above.
1. Stars that are smaller than super giants but bigger than the sun.
a. Giant stars
b. Super giants stars
c. Dwarf stars
d. Mega stars.

6. 1. Stars smaller than the sun and our earth which is about 12, 800 kilometres
across are called.
a. Giant stars
b. Super giant stars
c. Dwarf stars
d. Super stars.
1. What factor helps the astronomers determine the temperature of a star?
a. Size
b. Color
c. Movement
d. Distance
1. Why are stars considered as distant stars?
a. Each star is a big ball of burning gases.
b. Each star twinkles.
c. Each star is far.
d. Each star is bright.
1. What is a constellation?
a. Group of stars.
b. Group of stars close to each other.
c. Group of stars forming patterns.
d. Group of stars light years from the earth.
1. Which of the following diagrams explains the endless food nutrient cycle?
a. Green plants --- consumers --- decomposers---- nitrogen
b. Consumers --- green plants --- nitrogen ---- decomposers
c. Nitrogen -- consumers --- green plants --- decomposers
d. Decomposers --- consumers ----- green plants --- nitrogen
1. Which statements best explains the importance of forest to ecosystem?
a. The wood used in our building comes from the forest.
b. The river & lakes would become dry without the forest.
c. Forests are breeding ground of wildlife that supports balance of nature.
d. Forest provides food to human beings & other lower forms of animals.
1. A girl pedals her bicycle for five minutes and travels a distance of 120 meters. What
is the speed of the girl?
a. 600 meters per minute
b. 12 meters per minute
c. 5 meters per minute
d. 24 meters per minute
1. Which would require the least force to stop?
a. A car travelling at 120 km/hr.
b. A car travelling at 80 km/hr.
c. A car travelling at 60 km/hr.
d. A car travelling at 10 km/hr.
1. Why is Polaris a useful star?
a. It can be used to find directions.
b. It can be used by fortune tellers to predict the future.
c. It can be used to determined which period of the year is good for planting.
d. It is used as a good source of information.
1. What energy changes are shown by a moving airplane?
a. Mechanical to heat
b. Heat to mechanical
c. Electrical to heat
d. Heat to electrical
1. What is the energy stored in a dry cell?
a. Heat energy
b. Electrical energy
c. Mechanical energy
d. Chemical energy
1. Which car is decelerating?

7. CAR Velocity 1 Velocity 2
CAR A 50 m/s 2100 m/s
CAR B 20 m/s 20 m/s
CAR C 40 km/s 20 km/s
CAR D 10 km/s 25 km/s
a. Car C
b. Car A
c. Car D
d. Car B
1. Which part of the earth’s interior is made up loose solid rocks where continents and
oceans are found.
1
2
3
4
a. 1
b. 2
c. 3
d. 4
1. Why do stars seem to move across the sky?
a. Because of the earth’s rotation.
b. Because of the earth’s revolution.
c. Because of their distance from the earth
d. Because of their magnitude.