PAX Science NLN Exams collection 2023 (Answered) latest

PAX Science NLN Exams collection 2023 (Answered) latest 1. A person blows his breath into a straw that is placed in limewater. The limewater becomes cloudy because the person's breath contains A.) carbon dioxide. B.) hydrogen. C.) oxygen. D.) nitrogen. 2. A physician measures the pulse and blood pressure (BP) of all patients on a routine basis. Which of these measurements show the normal BP values for a resting adult patient? A.) 125/95 mm Hg B.) 120/80 mm Hg C.) 100/80 mm Hg D.) 72/120 mm Hg 3. A woman suddenly chokes on a piece of food and clutches frantically at her throat. An immediate remedy is to A.) have her bend forward and tell her to cough. B.) insert a finger or a blunt object toward the back of the mouth. C.) apply quick, hard pressures successively to her abdomen, just beneath her diaphragm. D.) phone "emergency" for help. 4. An unknown gas is more dense than air, does not support combustion, and turns a limewater solution cloudy. This gas is most probably A.) ammonia. B.) methane. C.) carbon dioxide. D.) hydrogen. 5. Human testes produce A.) eggs. B.) follicle stimulating hormone. C.) growth hormone. D.) spermatozoa. 6. If a red light is passed through a dilute solution of chlorophyll solution, the spectrophotometer will detect what amount of transmittance of this light? A.) 100% B.) 50 - 75% C.) Less than 25% D.) None - answer: 7. In diagnostic testing, the electroencephalogram permits the physician to A.) examine the impulses of the specialized muscle cells of the heart. B.) examine the impulses of the nerve cells within the brain. C.) measure the pressure within the eye. D.) measure the amount of air upon exhalation. 8. To sterilize a metal probe in the office, a dentist could use a steam sterilizer. If unavailable, the next most effective method to sterilize the instrument would be A.) boiling it in water for 15 minutes. B.) dipping it into a concentrated acid solution. C.) heating it in a hot air oven at 160°C for 20 minutes. D.) washing it in soap and water. 9. In varieties of matter, the term heterogeneous may be applied to A.) elements, but not compounds. B.) compounds, but not elements. C.) compounds and elements, but not mixtures. D.) mixtures, but not elements or compounds. 10. Heat energy is absorbed in which of these phase changes? A.) Br2 (l) - Br2(s) B.) Br2 (g) -- Br2(l) C.) Br2 (l) - Br2(g) D.) Br2 (g) - Br2(s) 11. Periodontitis is an inflammatory condition of the A.) gum tissue that surrounds the neck of each tooth. B.) pulp that contains nerve cells and blood vessels of the tooth. C.) dentin that surrounds the soft part of a tooth. D.) enamel that provides a hard surface for chewing 12. The atoms of an element with seven valence electrons are most probably classified as A.) metals. B.) nonmetals. C.) metalloids. D.) noble gases 13. The inherited factors that are transmitted in an organism from generation to generation are called its A.) homozygote. B.) heterozygote. C.) genotype. D.) phenotype. 14. The process of nuclear cell division in the cell reproduction of plants differs from mammals. A major difference is that A.) homologous chromosomes are paired. B.) centrioles are replicated. C.) spindle fibers are missing. D.) cell plates are synthesized. 15. Unicellular organisms that have a nucleus and can swim with the aid of cilia are examples of A.) monerans. B.) plants. C.) fungi. D.) protozoans. 16. Which of these conditions is associated with smoking? A.) Esophageal varices. B.) Tonsillitis. C.) Emphysema. D.) Blindness. 17. Which of these equations best illustrates a synthesis reaction? A.) 2Na + Cl2 - 2NaCl B.) NaOH + HCl - NaCl + H2O C.) 2H2O2 - 2H2O + O2 D.) CH4 + 2O2 - CO2 + 2H2O 18. Which of these hydrocarbons is a member of the benzene family? A.) Toluene. B.) Ethyne. C.) Propanone. D.) Methanol 19. Which of these quantities is most closely associated with an object's inertia? A.) Weight. B.) Energy. C.) Power. D.) Mass. 20. Which of these sequences of anatomic organization, from the simplest level to the most complex, is the correct sequence? A.) From tissue, organ, organ system to organism. B.) From organ system, organ, tissue to organism. C.) From tissue, organ system, organ to organism. D.) From organ, organ system, tissue to organism 21. Which of these single instruments may be used to measure the current flowing through a circuit? A.) A voltmeter. B.) An ammeter. C.) A potentiometer. D.) An ohmmeter. 22. Which of these temperatures is known as Absolute Zero? A.) 0°C B.) 0 K C.) positive 273°C D.) negative 273 K 23. Which part of the human central nervous system controls voluntary movements? A.) Spinal cord. B.) Cerebellum. C.) Cerebrum. D.) Medulla. 24. Within which of these structures of the female reproductive tract is the human egg fertilized? A.) Uterus. B.) Fallopian tube. C.) Vagina. D.) Cervix. 25. You cut your finger rather deeply while slicing an apple. Which of these actions should you take first? A.) Apply a sterile adhesive bandage. B.) Press the cut surface to stop the flow of blood. C.) Swab the wound with mild antiseptic. D.) Wash the wound continuously with cold running water. 26. A lens that focuses distant light to a single point is known as a A.) converging lens. B.) diverging lens. C.) concave lens. D.) prismatic lens. - answer: converging lens. 27. A magician rapidly pulls a tablecloth from a table, leaving the dishes undisturbed. Which of these principles of physics explains this "trick"? A.) Gravitational force depends directly on mass. B.) Objects at rest tend to remain at rest. C.) Force equals mass times acceleration. D.) An object traveling at constant velocity has no net force on it. - answer: Objects at rest tend to remain at rest. 28. A quantity that has both magnitude and direction is called a(n) A.) resultant. B.) scalar. C.) vector. D.) undefined unit. - answer: vector. 29. A recently discovered species has these characteristics: amniotic eggs, a four-chambered heart, and lightweight, honeycombed bones. Which of these ADDITIONAL characteristics is likely to be present? A.) Mammary glands. B.) External fertilization. C.) Ectotherms. D.) Feathers for flying. - answer: Feathers for flying. 30. Amnesia in humans is the loss of memory. Which of these parts of the brain has been affected when someone is suffering from amnesia caused by head trauma? A.) Cerebral cortex. B.) Cerebellum. C.) Medulla oblongata. D.) Spinal cord. - answer: Cerebral cortex. 31. An example of the most complex level of organization in a frog is the A.) epithelium. B.) striated muscle. C.) respiratory system. D.) stomach. - answer: respiratory system. 32. Anaerobic respiration occurs in muscle tissue when it cannot get sufficient oxygen to function aerobically. Which of these conditions is most likely to directly result from this? A.) Cramps. B.) Necrosis. C.) Bleeding. D.) Swelling. - answer: Cramps 33. Enzymes that are involved in biochemical reactions are organic A.) colloids. B.) catalysts. C.) cathodes. D.) constants. - answer: Catalysts 34. In a study on the effect of cocaine on the brains of rats, two groups of animals were selected. Each day, Group A was injected with the drug dissolved in water, whereas Group B was injected with water alone. In such a study Group B is included as A.) an experimental group. B.) a test group. C.) an exercise group. D.) a control group. - answer: a control group. 35. In corn plants, the gene that codes for the presence of chlorophyll is sometimes missing. The resulting seedlings are albino and will not survive. This lethal gene appears in corn populations because A.) the soil nutrients will not allow the plant to produce chlorophyll. B.) the parent plants that produced the seeds carried the recessive gene for the albino trait. C.) the farmer used herbicides, which destroyed the chlorophyll in the seedlings. D.) the seeds were old and stored improperly, resulting in the lethal trait. - answer: the parent plants that produced the seeds carried the recessive gene for the albino trait 36. In the reaction of iron with water shown below, what coefficient must be placed before the iron (Fe) to balance the reaction? Fe + 4H2O ° Fe3O4 + 4H2 A.) 2 B.) 3 C.) 4 D.) 6 - answer: 3 37. A circuit contains three 3-ohm (W) resistors in series. What is the equivalent resistance of this combination? - answer: 9W 38. An example of an adaptation to prevent water loss in plants is - answer: waxy epidermis 39. At room temperature, which of these substances exists as diatomic molecules? - answer: oxygen 40. Compounds with the same type and number of atoms and the same chemical bonds but different spatial arrangements of these bonds and atoms are called - answer: structural isomers. 41. The calorie and the kilocalorie are units of - answer: energy 42. The force of gravity on an object is that object's - answer: weight 43. The light sensitive cells of the eye are called rods and cones. Which of these layers of the eye are they found in? - answer: retina 44. The meiotic division of cells leads to the production of cells that - answer: contain half the usual number of chromosomes. 45. The most probable area of study that would show the prevalence of mental illness in midManhattan is that of - answer: epidemiology 46. The normal boiling temperature for water is 100° when measured on which of these scales? - answer: celsius 47. What is the pH of a solution whose H+ ion concentration is 1 x 10-2 mole per liter? - answer: 2 48. When a column of air is vibrating at the same rate as a tuning fork, the process is referred to as - answer: resonance 49. When a population is in Hardy-Weinberg equilibrium, which of these conditions must be present? - answer: The population is isolated from other populations. 50. When three resistors of 10.0 ohms each are placed in series, the total resistance is - answer: 30.0 ohms 51. Which of these changes occurs in the kidneys when a person becomes dehydrated? - answer: The filtration rate of water remains constant and the reabsorption of water increases. 52. Which of these could be stopped by a sheet of paper? - answer: Alpha particle 53. Which of these is an example of a simple machine? - answer: lever, pulley, inclined plane 54. Which of these organisms might be found in contaminated well water? - answer: Giardia 55. Which of these processes occurs at a neuromuscular junction? - answer: Impulse transmission. 56. 1 kilogram (kg) of solid X at 10°C and 1 kg of solid Y at 10°C each absorb 5 joules of heat energy. The final temperatures of X and Y are 15°C and 20°C, respectively. Compared to X, Y must have a lower - answer: specific heat 57. A drop of dilute ammonium hydroxide (NH4OH) is placed on one side of a slide containing a large number of swimming paramecium. Under this condition, which of these behaviors of the paramecia will be observed? - answer: They will eventually all swim away from the ammonium hydroxide. 58. A physician measures the pulse and blood pressure (BP) of all patients on a routine basis. Which of these measurements show the normal BP values for a resting adult patient? - answer: 120/.80 mmHg 59. Which of these processes is responsible for the recorded production of CO2 by yeast cells from sugar solution? - answer: anaerobic respiration 60. In classical physics, light is viewed as part of the electromagnetic spectrum, traveling in the form of transverse waves. Quantum physics proposes that light is composed of quanta called - answer: photons 61. Enzymes that are involved in biochemical reactions are organic - answer: catalysts 62. How much current is drawn by a light bulb that has a resistance of 100 R with a voltage of 110 V? (V = IR) - answer: 1.1 amperes 63. Sodium will react most readily with - answer: chlorine 64. The watt is a unit of - answer: power 65. The boiling point of liquid nitrogen at one atmosphere pressure is 77 K. This temperature is equivalent to. - answer: - 196 C 66. The energy associated with an object's position is termed - answer: potential energy 67. The extension of a neuron that carries the impulse to another cell is called - answer: axon 68. What is the correct sequence in the life cycle of a moth? - answer: Egg, larva, pupa, adult. 69. When water passes from a region of greater concentration to a region of lesser concentration through a selectively permeable membrane, the process is known as - answer: osmosis 70. Which of these experiments would be an effective way to determine the distribution of touch receptors in the skin? - answer: Have a blindfolded student tell when a bristle placed lightly against the skin is felt. 71. Which of these processes is used to free contaminated water of bacteria? - answer: Passing it through charcoal. 72. Which of these structures produces sperm cells in human males? - answer: testes 73. What is a gram stain? - answer: an important technique used in the laboratory thatdistinguishes between different kinds of bacterial cell walls. 74. Reducing the use of aeresol cans has contributed to the decrease of? - answer: the destruction of the ozone layer 75. The atomic number of flourine is 9. How many electrons are contained in the second principal energy level of a flourine atom in the ground state? - answer: 7 76. The second law of thermodynamics states that with every spontaneous process, the entropy of the universe - answer: increases 77. When blood is filtered in the kidney and urine is produced, red blood cells and plasma proteins do not pass through the blood capillaries. This occurs because - answer: blood and plasma proteins are needed by the body, so they do not get filtered out into the kidney. 78. Which of these germ layers gives rise to the skin? - answer: ectoderm 79. A material that settles out of a reaction is termed a - answer: colloid 80. According to the Ideal Gas Equation (PV = nRT), if the temperature and amount of gas are kept constant, what will be the effect of an increase in pressure on the volume of a gas? - answer: As the pressure increases, the volume decreases. 81. All living cells contain cytoplasm. Cytoplasm is important because it - answer: controls what moves in and out of the cell. 82. All of these groups of land plants produce seeds EXCEPT - answer: evergreen trees, such as pines and spruces. 83. Charles Darwin's theory of evolution suggests that the reason for the various differences between species is a result of - answer: natural selection 84. In order to observe the endoplasmic reticulum in a cell, a scientist would use - answer: an electron microscope 85. Scientists have discovered that most vertebrates have cone cells in their eyes, which distinguish colors in daylight. The rods are more sensitive to light, but do not distinguish colors. If a mammal is nocturnal - answer: there are fewer cones and a greater concentration of rods to collect the minimal light for night vision. 86. The functional group present in all alcohols is the - answer: hydroxyl group 87. The scientific name of the wolf is Canis lupus. The name indicates the wolf's - answer: genus and species 88. The weight of an adult human in newtons (N) is closest to - answer: 500 N 89. When two atoms share a pair of electrons, the bond between them is called - answer: covalent 90. When a sperm and egg join to form a zygote in humans, what determines the sex of the child that is produced? - answer: sperm 91. Which of these arrangements of atoms is found in all alcohols? - answer: C-OH 92. Which of these units is associated with magnitude, but not direction? - answer: Time 93. Which aspect of a simple machine is represented by the ratio work output to work input? - answer: Actual mechanical advantage. 94. 30 students in a class carefully measure the length and width of 20 peanut shells. They also count the number and note the size of the peanuts inside. This information is recorded on various graphs showing the numbers of nuts and the different sizes. The collected evidence of the peanuts gives the students an idea of the extent of - answer: variation within a species. 95. A lens that focuses distant light to a single point is known as a - answer: converging lens. 96. During exercise, a person's respiratory rate increases due to - answer: an increase in CO2 concentration in the blood. 97. Ganglia are made up of a cluster of - answer: neurons. 98. To determine the optimum conditions for the activity of a digestive enzyme, it would be necessary to test its activity over a range of - answer: temperature, pH and substrate concentration. 99. Which of these findings suggests a serious illness from a urinalysis? - answer: Presence of glucose and protein. 100. As part of the human immune response, which of these cells are responsible for producing antibodies? - answer: lymphocytes 101. A cell which manufactures a large amount of protein for export would have an abundance of organelles called - answer: ribosomes 102. A lab technician has the choice of four different enzymes to use in an experiment that will run at 25°C. The optimal temperatures of enzymes using the Kelvin scale are: Enzyme A: 273 K, Enzyme B: 298 K, Enzyme C: 310 K, Enzyme D: 325 K. Which enzyme would be the best to use in this experiment? - answer: Enzyme B 103. If a person is fasting for 24 hours and ingests no carbohydrates, the liver will provide for the body's need by - answer: converting glycogen into glucose. 104. The physics principle that is primarily used in developing a rollercoaster ride is - answer: centripetal force 105. Whole blood of type AB can be transfused to people with which of these types of blood? - answer: AB only 106. Which of these organ systems does NOT provide for the excretion of substances? - answer: lymphatic 107. Which of these processes is illustrated by the spreading out of ammonia vapor in a closed room? - answer: Diffusion 108. Which human body system does meiosis occur in? - answer: reproductive 109. Which biochemical family do starch and glycogen belong in? - answer: carbohydrates 110. The succession of flora and fauna encountered while climbing a mountain in the northern hemisphere is similar to that found when traveling from the base of the same mountain in which of these general directions? - answer: North