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Majorship LET Reviewer

LET Reviewer for Biological Science
LET Reviewer for Biological Science

101. Which element is not recycled throughout an ecosystem by the process of photosynthesis and respiration?
A. carbon
B. nitrogen
C. oxygen
D. hydrogen

102. The gas that is most abundant in the air is
A. oxygen
B. nitrogen
C. carbon dioxide
D. argon

103. The greatest source of indoor pollutant is
A. smog
B. radon
D. sunlight

104. All of the following are probable consequences of water related environmental problems except
A. Diarrhea
B. amoebiasis
C. typhoid fever
D. respiratory track infection

105. Overdraft is an overuse of groundwater, which makes the reservoirs of groundwater emptied and very seldom replenished especially during the summer months. Which among the following environmental problems related to soil is the probable consequence of overdraft?
A. soil pollution
B. land subsidence
C. soil erosion
D. deforestation

106. Plant nutrients such as nitrates and phosphates, which come from fertilizers and detergent, can cause algal bloom. What do you call the phenomenon on which a body of water which contains high concentrations of chemical elements required for life makes the produces bloom by directly nourishing most bacteria than aquatic organisms like fishes?
A. euthrophication
B. biomagnification
C. soil water intrusion

107. Which of the following best describes a non-metal?
A. they are ductile and malleable
B. they have high tensile strength
C. they are good insulators
D. they are hard and brittle

108. Which is an example of a heterogeneous mixture?
A. Distilled water
B. rubbing alcohol
C. Agua oxinada
D. concrete

109. Which of the following phase changes are exothermic?
A. sublimation and melting
B. evaporation and condensation
C.condensation and freezing
D. evaporation and deposition

110. Which grouping is composed of pure substances only?
A. fog, dew, brine
B. dew, dry ice, vinegar
C. ice, dry ice, table sugar
D. ice, table salt, fog

111. Which of the following best describes a mixture?
A. It is homogeneous
B. It has a definite composition
C. It changes the colors of common indicators
D. Its components are combined in any proportion

112. The state of matter that is characterized by strong attractive forces.
A. solid
B. liquid
C. gas

113. The components of ink can best be separated using
A. evaporation
B. filtration
C. centrifugation
D. chromatography

114. All of the following are chemical properties except
A. toxicity
B. corrosiveness
C. solubility
D. flammability

115. Which of the following statements is true?
A. Light has mass
B. Air has volume
C. Heat occupies space
D. Sound has both mass and volume

116. Which of the following is an intensive physical property?
A. mass
B. volume
C. color
D. length

117. When a pure crystalline yellowish substance is heated in vacuum, a greenish gas and a red powdery substance were produced. In which of the follo9wing will you classify the yellowish substance?
A. element
B. compound
C. mixture
D. pure substance

118. Isotopes are atoms that have the same atomic number but different mass numbers. It means also that isotopes are atoms that have
A. the same number of electrons but different number of protons
B. the same number of neutrons but different number of electrons
C. the same number of protons but different number of neutrons
D. the same number of protons but different number of electrons

119. This electrically neutral particle was discovered by Chadwick in 1932 with its mass slightly greater than that of proton?
A. electron
B. neutron
C. positron
D. neutrino

120. The spoilage of meat is delayed when kept in a refrigerator because the cold temperature
A. keeps the flies/ insects away
B. slows down the action of bacteria
C. changes the color and odor of meat
D. turns the water component of meat to ice

121. What happens to a given mass of fluid if heat flow into it?
A. It becomes denser
B. It becomes less dense
C. it becomes colder
D. It becomes heavier

122. During chemical changes or chemical reactions, which particles are gained, lost, or shared?
A. protons inside the nucleus
B. neutrons inside the nucleus
C. electrons in the outermost energy level
D. electrons in the innermost energy level

123. Which of the following radiation has the highest penetrating power?
A. alpha
B. beta
C. gamma

124. Which of the following statements explains why we feel cool after perspiring?
A. vapor in the air condenses in our skin
B. water coming out of our body is cold
C. pores in our skin allow cool air to enter
D. evaporating water in our skin produces a cooling effect

125. What is the most practical way to control pollution?
A. decreasing the population
B. more government control of industry
C. careful planning of environmental usage
D. slowing the rate of technological growth

126. Humans can cause rapid changes in the environment, sometimes producing catastrophic events. Which statement below is the best example of this concept?
A. lightning causes forest fire
B. shifting crustal plates cause an earthquake
C. changing seasonal winds cause flooding in an area
D. mountainside highway construction causes a landslide

127. How are latitude and longitude lines drawn?
A. latitude lines are parallel and longitude lines meet at the poles
B. latitude lines are parallel and longitude lines meet at the equator
C. longitude lines are parallel and latitude lines meet at the poles
D. longitude lines are parallel and latitude lines meet at the equator

128. The water part of the earth is also known as
A. lithosphere
B. hydrosphere
C. atmosphere
D. biosphere

129. The vibration of the earth's surface due to the release of stored energy when the deformed rock ruptures or returns to its original size and shape?
A. earthquake
B. tsunami
C. faulting
D. folding

130. What happens when air is heated?
A. It expands and it rises
B. It expands and sinks
C. It contracts and rises
D. It contracts and sinks

131. What do you call the phenomenon wherein there is a marked increase in the earth's surface temperature associated with radiation being trapped by its atmosphere?
A. Global warming
B. greenhouse effect
C. El Nino
D. La Nina

132. In the water cycle, which process is responsible for getting water into the atmosphere?
A. Condensation
B. evaporation
C. sublimation
D. melting

133. In majority of stars, the most common element is
A. oxygen
B. hydrogen
C. helium
D. nitrogen

134. The color of the hottest star is
A. red
B. blue
C. yellow
D. bluish white

135. If you want to cook boiled eggs while in the mountains you should
A. use hotter flame
B. boil the eggs for a longer time
C. boil the eggs for a shorter time
D. not boil the eggs, because the water temperature won't get hot enough to cook them

136. A metal lid could not be unscrewed from its glass jar. Which of the following is the best way to unscrew it from the jar?
A. Invert the jar with the lid in a very hot water for a few seconds
B. Invert the jar with the lid in a very cold water for a few seconds
C. invert the jar with the lid in cold and then in hot water for a few seconds
D. invert the jar with the lid in hot and then in cold water for a few seconds

137. It refers to the temperature at which the molecules have the lowest possible kinetic energy
A. absolute zero
B. melting point
C. boiling point
D. freezing point

138. Why does apiece of metal feel colder than a piece of wood at the same temperature?
A. metal is colder than wood
B. metals allow heat to flow through them easily
C. metals have higher specific heat than wood
D. none of the above

139. What accounts for the cooling effect inside the refrigerator?
A. the refrigerator is properly insulated
B. vaporization of the refrigeration fluid
C. compression of the refrigerant into liquid
D. the motor converts electrical energy into thermal energy

140. What do you call animals that feed on both plant and meat?
A. herbivores
B. carnivores
C. omnivores
D. insectivores

141. After drinking dirty water, a student developed bloody diarrhea and liver problems in a few weeks later. Which of the following is the most likely cause of the disease?
A. Paramecium
B. dinoflagellates
C. amoeba
D. euglena

142. Chemical produced by some bacteria that can kill or weaken other bacteria
A. antitoxins
B. antibodies
C. antibiotics
D. antiseptic

143. When light travels from water to air, what happens to its speed?
A. It increases
B. It decreases
C. It remains the same

144. In which medium can sound travel the fastest?
A. wood
B. water
C. air
D. metals

145. The sound produced by a piano differs from that of the violin even if both sounds have the same pitch and loudness because of
A. frequency
B. intensity
C. overtones
D. amplitude

146. What do you call a type of mixture that scatters light passing through it?
A. solution
B. colloid
C. suspension

147. Fleming is a scientist made famous due to his fortunate accidental discovery of penicillin. This is an example of
A. scientific destiny
B. serendipity
C. medical truth
D. hard work

148. Why is water considered a universal solvent?
A. It has a high density
B. It has a high specific heat
C. It dissolves polar and non – polar substances
D. It dissolve both polar and ionic substance

149. The study of matter with focus on motion, forces and energy?
A. physics
B. chemistry
C. biology
D. earth science

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