0% Biology - NAT ( National Aptitude Test )Biology refers to the biology subject on the National Aptitude Test (NAT), a standardised test for admissions in Pakistan. 1 / 200Which of the following is a micronutrient required by plants? Nitrogen Potassium Iron Phosphorus 2 / 200The molecule that carries genetic information in most organisms is: DNA Protein ATP RNA 3 / 200 Which of the following is an example of a density-independent factor that could limit population growth? Competition for resources Disease Volcanic eruption Predation 4 / 200In the lac operon of E. coli, the repressor protein is inactivated by binding to: Glucose RNA polymerase Lactose Promoter 5 / 200A woman with blood type A (whose father was type O) marries a man with blood type B (whose father was type O). What is the probability that their first child will have blood type O? 100% 0% 50% 25% 6 / 200Which part of the human brain is responsible for controlling balance and coordination? Medulla Oblongata Thalamus Cerebellum Cerebrum 7 / 200In a typical ecosystem, which trophic level has the maximum biomass? Primary Consumers Producers Secondary Consumers Tertiary Consumers 8 / 200The theory of natural selection was proposed by: Charles Darwin Louis Pasteur Gregor Mendel Robert Hooke 9 / 200The hormone that promotes cell elongation in plants is: Abscisic Acid (ABA) Cytokinin Ethylene Auxin 10 / 200The basic structural and functional unit of life is the: Organ Organelle Tissue Cell 11 / 200A competitive inhibitor of an enzyme: Denatures the enzyme permanently Binds to a site other than the active site Binds to the active site and resembles the substrate Alters the enzyme's active site 12 / 200Which stage of cellular respiration produces the majority of ATP? Oxidative phosphorylation Pyruvate decarboxylation Glycolysis The Krebs cycle 13 / 200In the fluid mosaic model of the plasma membrane, what do the "mosaic" aspects represent? The phospholipid bilayer The fluid nature of lipids The cholesterol molecules The embedded proteins 14 / 200Which organelle is primarily responsible for the synthesis of phospholipids and steroids? Golgi Apparatus Rough Endoplasmic Reticulum Smooth Endoplasmic Reticulum Lysosome 15 / 200Which of the following hormones is NOT produced by the anterior pituitary gland? Growth hormone (GH) Thyroid-stimulating hormone (TSH) Antidiuretic hormone (ADH) Follicle-stimulating hormone (FSH) 16 / 200In a food chain, if the energy available at the producer level is 10,000 J, what is the approximate energy available to a tertiary consumer? 50 J 1000 J 10 J 100 J 17 / 200In the human heart, the chamber that pumps oxygenated blood to the body via the aorta is the: Right Ventricle Left Ventricle Right Atrium Left Atrium 18 / 200 The phase of mitosis where chromosomes align at the equatorial plate is: Anaphase Prophase Metaphase Telophase 19 / 200According to Mendel's law of segregation: Characteristics are inherited as discrete units. The dominant allele is always expressed. The two alleles for a single trait separate from each other during gamete formation. Alleles for different traits segregate independently of one another during gamete formation. 20 / 200Which of the following is a disaccharide? Starch Sucrose Fructose Glucose 21 / 200During the light-dependent reactions of photosynthesis, the primary function of photosystem II is to: Fix carbon dioxide Split water molecules and release oxygen Synthesize ATP Reduce NADP+ to NADPH 22 / 200Which of the following is a disaccharide? Fructose Glucose Starch Sucrose 23 / 200Which of the following is a characteristic feature of prokaryotic cells? Linear DNA Membrane-bound organelles Presence of a nuclear membrane Cell wall made of peptidoglycan 24 / 200Which kingdom includes algae and protozoa? Protista Fungi Plantae Monera 25 / 200Which of the following is NOT a type of RNA? rRNA mRNA xRNA tRNA 26 / 200The process by which plants respond to light is called: Thigmotropism Hydrotropism Phototropism Geotropism 27 / 200Which hormone decreases blood calcium? PTH (Parathyroid Hormone) Calcitonin Insulin Aldosterone 28 / 200Which part of the brain is responsible for coordinating muscle movements and maintaining balance? Cerebrum Hypothalamus Cerebellum Medulla oblongata 29 / 200Which of the following is a decomposer in an ecosystem? Fungus Rabbit Grass Hawk 30 / 200In humans, fertilization normally occurs in the: Fallopian tube Cervix Ovary Uterus 31 / 200Which plant hormone is primarily involved in promoting cell elongation and is responsive to light and gravity? Auxin Ethylene Cytokinin Abscisic Acid 32 / 200 In humans, the role of bile in digestion is to: Break down starch Absorb vitamins Emulsify fats Digest proteins 33 / 200Which of the following is a unicellular organism? Mushroom Earthworm Amoeba Fern 34 / 200 The largest organ in the human body is the: Brain Liver Skin Large intestine 35 / 200 In the electron transport chain, the movement of protons (H+) from the intermembrane space into the mitochondrial matrix occurs through which specific protein complex? Coenzyme Q Cytochrome c ATP synthase NADH dehydrogenase 36 / 200The process by which plants lose water vapor through their leaves is called: Respiration Evaporation Photosynthesis Transpiration 37 / 200In a dihybrid cross between two heterozygous individuals (RrYy × RrYy), what proportion of the offspring would be expected to show both recessive traits? 3/16 1/16 9/16 1/4 38 / 200The light-independent reactions (Calvin Cycle) of photosynthesis occur in t Cytoplasm Stroma of the chloroplast Inner mitochondrial membrane Thylakoid membrane 39 / 200Which of the following is NOT a function of the vertebrate skeleton? Protection of internal organs Storage of minerals Synthesis of hormones Production of blood cells 40 / 200The functional unit of the kidney where filtration, reabsorption, and secretion occur is the: Ureter Nephron Bowman's capsule Glomerulus 41 / 200The scientific study of heredity is called: Genetics Physiology Ecology Evolution 42 / 200The largest gland in the human body is the: Liver Pituitary Thyroid Pancreas 43 / 200Which vitamin deficiency causes rickets? Vitamin A Vitamin C Vitamin D Vitamin K 44 / 200In a population in Hardy-Weinberg equilibrium, the frequency of the recessive allele for a trait is 0.3. What is the frequency of heterozygous individuals in the population? 0.21 0.09 0.42 0.49 45 / 200Which part of the flower develops into a fruit? Stamen Ovary Sepal Petal 46 / 200 In plants, the vascular tissue responsible for transporting organic nutrients (sugars) from leaves to other parts is the: Cambium Xylem Epidermis Phloem 47 / 200Which cells secrete glucagon? Alpha cells of pancreas Chief cells of stomach Delta cells of pancreas Beta cells of pancreas 48 / 200The final electron acceptor in the aerobic respiration electron transport chain is: Oxygen (O₂) Water (H₂O) NAD+ ATP synthase 49 / 200Which vitamin is produced by the human body when exposed to sunlight? Vitamin A Vitamin D Vitamin B12 Vitamin C 50 / 200In ecological terms, organisms that produce their own food are called: Producers Decomposers Heterotrophs Consumers 51 / 200In the nephron, most reabsorption of water and solutes occurs in the: Loop of Henle Distal convoluted tubule Proximal convoluted tubule Glomerulus 52 / 200Which part of the flower develops into a fruit after fertilization? Ovary Stigma Ovule Style 53 / 200Which hormone is released during stress? Insulin Adrenaline GH Calcitonin 54 / 200Which plant hormone promotes cell elongation and is involved in phototropism? Gibberellin Cytokinin Abscisic acid Auxin 55 / 200Which of the following is a decomposer in an ecosystem? Grass Rabbit Hawk Fungus 56 / 200The largest lymphoid tissue in the body is the: Liver Bone marrow Tonsils Spleen 57 / 200A person who has the antigen B on the surface of their red blood cells has a blood type of ______ and can receive blood from ______. B; B only O; O only AB; A, B, AB, and O B; B and O 58 / 200In an ecosystem, the primary consumers are always: Decomposers Herbivores Carnivores Producers 59 / 200The largest store of energy in the body is in the form of: Amino acids Fatty acids Glycogen Glucose 60 / 200The exchange of gases in the lungs occurs through the process of: Diffusion Facilitated diffusion Active transport Osmosis 61 / 200An individual suffers from a disease where their immune system attacks the myelin sheaths of their own neurons. This is an example of: An autoimmune disease An acquired passive immunity An allergic reaction An immunodeficiency disease 62 / 200The scientific name of the human species is: Homo erectus Homo sapiens Homo neanderthalensis Homo habilis 63 / 200A patient presents with muscle cramps and fatigue. A blood test reveals low sodium levels. This imbalance is most likely due to improper functioning of which hormone? Aldosterone Insulin Glucagon Thyroxine 64 / 200Which of the following best describes the role of tRNA in protein synthesis? It carries the genetic code out of the nucleus. It is a major component of the ribosome. It carries amino acids to the ribosome. It provides the template for the amino acid sequence. 65 / 200 Photosynthesis primarily occurs in which part of the plant cell? Vacuoles Chloroplasts Nucleus Mitochondria 66 / 200In a classic DNA semi-conservative replication experiment, if bacteria are grown in a medium containing 15N (heavy isotope) and then transferred to a medium containing 14N (light isotope) for two generations, what would be the ratio of hybrid DNA (15N-14N) to light DNA (14N-14N)? 1:1 1:3 All light All hybrid 67 / 200The human heart has how many chambers? 4 5 3 2 68 / 200Which of the following is a function of the skeletal system? Digestion Respiration Blood circulation Support and protection 69 / 200A permanent change in the DNA sequence of a gene is called a: Plasmid Mutation Mutagen Phenotype 70 / 200The process by which plants make their own food using sunlight is called: Respiration Photosynthesis Digestion Transpiration 71 / 200Which of the following is a density-dependent factor that can limit population growth? Volcanic eruption Drought Forest fire Competition for food 72 / 200In a food chain, if the primary producer has 10,000 units of energy, approximately how much energy would be available to a tertiary consumer? 10 units 10,000 units 1,000 units 100 units 73 / 200Blood clotting requires: Vitamin K Vitamin A Vitamin D Vitamin B12 74 / 200Which type of blood vessel carries blood away from the heart? Arteries Venules Veins Capillaries 75 / 200The human respiratory system includes all EXCEPT: Trachea Bronchi Alveoli Aorta 76 / 200The kingdom that includes organisms like algae and protozoa, which are primarily unicellular and eukaryotic, is: Plantae Protista Monera Fungi 77 / 200In the genetic code, a sequence of three bases is called a: Chromosome Codon Nucleotide Gene 78 / 200 The process by which DNA makes a copy of itself is called: Replication Mutation Transcription Translation 79 / 200 In a population in Hardy-Weinberg equilibrium, the frequency of the recessive allele is 0.3. What is the frequency of heterozygous individuals? 0.21 0.42 0.49 0.09 80 / 200The theory of evolution by natural selection was primarily proposed by: Gregor Mendel Charles Darwin Jean-Baptiste Lamarck Alfred Russel Wallace 81 / 200Which of the following is NOT a part of the cell theory? The cell is the basic unit of life Cells arise from pre-existing cells All cells have a nucleus All living things are made of cells 82 / 200Which of the following is a correct pair of a disease and its related malfunctioning organ? Jaundice - Kidney Emphysema - Heart Hepatitis - Liver Goiter - Brain 83 / 200Cushing's syndrome is due to an excess of: Aldosterone Cortisol FSH Insulin 84 / 200The main function of roots in plants is: Photosynthesis Gas exchange Reproduction Absorption of water and minerals 85 / 200Which of the following correctly describes the direction of impulse transmission in a neuron? Cell body → dendrite → axon Axon → cell body → dendrite Dendrite → cell body → axon Cell body → axon → dendrite 86 / 200The process of double fertilization is a unique characteristic of: Bryophytes Gymnosperms Angiosperms Pteridophytes 87 / 200The smallest bone in the human body is found in the: Foot Nose Hand Ear 88 / 200A non-competitive inhibitor of an enzyme: Binds to the active site Increases the Km value Is overcome by adding more substrate Binds to a site other than the active site 89 / 200Which blood vessels carry blood away from the heart? Veins Capillaries Arteries Venules 90 / 200The process by which mRNA is synthesized from a DNA template is called: Translation Transformation Replication Transcription 91 / 200Which of the following is a characteristic feature of angiosperms? Double fertilization Presence of vascular tissue Production of cones Seeds not enclosed in an ovary 92 / 200The largest gland in the human body is the: Pituitary Liver Pancreas Thyroid 93 / 200Enzymes function by: Producing heat Increasing activation energy Changing pH Decreasing activation energy 94 / 200During which phase of mitosis do the sister chromatids separate and move to opposite poles of the cell? Metaphase Prophase Anaphase Telophase 95 / 200Which vitamin is produced by the human body when exposed to sunlight? Vitamin A Vitamin B12 Vitamin C Vitamin D 96 / 200 Insulin and glucagon are hormones secreted by the pancreas that regulate blood glucose levels. They are secreted by the: Gallbladder Hepatic cells Islets of Langerhans Acinar cells 97 / 200Absorption of food is greatest in the: Duodenum Ileum Jejunum Colon 98 / 200The dark reaction of photosynthesis (Calvin cycle) occurs in the: Stroma Inner mitochondrial membrane Grana Thylakoid membrane 99 / 200Which of the following is a greenhouse gas that contributes to global warming? Oxygen Nitrogen Methane Hydrogen 100 / 200During protein synthesis, the process of transcription occurs in the: Cytoplasm Mitochondria Nucleus Ribosome 101 / 200DNA replication is: Conservative Non-conservative Semi-conservative Dispersive 102 / 200The basic structural and functional unit of life is: DNA Organ Cell Tissue 103 / 200A man with blood group A (genotype IAi) marries a woman with blood group B (genotype IBi). What is the possible blood group of their offspring? A, B, AB, or O AB only A, B, or O only A or B only 104 / 200Which of the following cells of the immune system are responsible for producing antibodies? Helper T-cells Memory cells Plasma cells Cytotoxic T-cells 105 / 200Which part of the brain controls balance and coordination? Cerebellum Cerebrum Medulla oblongata Hypothalamus 106 / 200The process by which a piece of a chromosome breaks off and attaches to another chromosome is known as: Deletion Inversion Translocation Duplication 107 / 200Which of the following is a function of the skeletal system? Regulation of body temperature Production of blood cells Transportation of nutrients Production of hormones 108 / 200The main function of the mitochondria is: Energy production Secretion of hormones Storage of genetic material Protein synthesis 109 / 200A man with a normally pigmented father and an albino mother has a child with an albino woman. What is the probability that their first child will be albino? (Assume albinism is an autosomal recessive trait). 100% 0% 25% 50% 110 / 200 In humans, the XX chromosomes correspond to: Female Male Hermaphrodite Sterile individual 111 / 200In a food chain, grass is eaten by a grasshopper, which is eaten by a frog, which is eaten by a snake. The secondary consumer is the: Grass Snake Grasshopper Frog 112 / 200Which of the following is a biotic factor in an ecosystem? Temperature Soil Plants Water 113 / 200Which of the following is a renewable resource? Petroleum Solar energy Natural gas Coal 114 / 200The part of the neuron that receives incoming signals from other neurons is the: Myelin sheath Soma (cell body) Axon Dendrite 115 / 200The central nervous system consists of: Sensory organs only Nerves throughout the body Brain and peripheral nerves Brain and spinal cord 116 / 200Dwarfism is due to a deficiency of: Thyroxine Insulin GH (Growth Hormone) Estrogen 117 / 200A point mutation that changes a codon coding for an amino acid into a stop codon is called a: Nonsense mutation Silent mutation Missense mutation Frameshift mutation 118 / 200The causative agent of Tuberculosis is: Mycobacterium tuberculosis Salmonella typhi Streptococcus pneumoniae Mycobacterium leprae 119 / 200Which of the following is a characteristic of C4 plants but not C3 plants? They have a higher rate of photorespiration They have Kranz anatomy They keep their stomata closed during the day They fix carbon dioxide at night 120 / 200In which organelle does cellular respiration primarily occur? Nucleus Mitochondria Ribosome Chloroplast 121 / 200Which gas do plants absorb from the atmosphere during photosynthesis? Hydrogen Nitrogen Carbon dioxide Oxygen 122 / 200The process of cell division that results in two identical daughter cells is called: Replication Mitosis Meiosis Fertilization 123 / 200Which of the following is a nitrogenous base found in DNA but not in RNA? Cytosine Uracil Thymine Guanine 124 / 200Which of the following is a greenhouse gas? Carbon dioxide Nitrogen Hydrogen Oxygen 125 / 200The main function of white blood cells is to: Transport nutrients Fight infection Carry oxygen Clot blood 126 / 200In a population, the total aggregate of genes is called the: Gene frequency Genome Genotype Gene pool 127 / 200 A man with blood group A (genotype IAi) and a woman with blood group B (genotype IBi) can have a child with which of the following blood groups? A, B, AB, or O A only AB only B only 128 / 200Which organelle is responsible for protein synthesis? Mitochondria Ribosome Endoplasmic reticulum Golgi apparatus 129 / 200Photosynthesis occurs in which part of the plant cell? Chloroplast Vacuole Mitochondria Nucleus 130 / 200During inhalation in humans, which of the following occurs? The diaphragm contracts and flattens. The internal intercostal muscles contract. The diaphragm relaxes and moves upwards. The volume of the thoracic cavity decreases. 131 / 200The process of water movement through a plant and evaporation from leaves is called: Photosynthesis Osmosis Transpiration Respiration 132 / 200Which gland is both endocrine and exocrine? Pancreas Adrenal Thyroid Pituitary 133 / 200Goitre occurs due to a deficiency of: Calcium Sodium Iodine Iron 134 / 200Which of the following is a function of the liver? Bile production Blood filtration Oxygen exchange Insulin production 135 / 200The smallest bone in the human body is found in the: Hand Ear Nose Foot 136 / 200In the human eye, the part that controls the amount of light entering is the: Lens Pupil Cornea Retina 137 / 200Which of the following statements correctly describes the difference between oxidative and substrate-level phosphorylation? Substrate-level phosphorylation uses a proton gradient, while oxidative phosphorylation does not. Oxidative phosphorylation is directly coupled to the electron transport chain, while substrate-level phosphorylation involves a direct enzymatic transfer of a phosphate group. Oxidative phosphorylation occurs in the cytoplasm, while substrate-level occurs in the mitochondria. Only substrate-level phosphorylation produces ATP. 138 / 200Which vitamin is fat-soluble and its deficiency can lead to night blindness? Vitamin D Vitamin A Vitamin C Vitamin B 139 / 200The movement of water from the soil into the root xylem, without entering the living cells, is through the: Apoplast pathway Transmembrane pathway Active transport Symplast pathway 140 / 200 During DNA replication, the enzyme that synthesizes the new DNA strand by adding nucleotides is: Helicase DNA ligase DNA polymerase Restriction enzyme 141 / 200The process of copying DNA into mRNA is called: Replication Transcription Translation Transformation 142 / 200Which of the following is an example of an innate behavior? A bird building its first nest A human speaking a language A chimpanzee using a tool A dog learning to sit on command 143 / 200In plants, the Casparian strip is located in the: Pericycle Epidermis Endodermis Cortex 144 / 200TSH (Thyroid-Stimulating Hormone) acts on the: Pancreas Gonads Adrenal Thyroid 145 / 200The enzyme that digests proteins in the stomach is: Trypsin Pepsin Lipase Amylase 146 / 200The process of cell division that results in two identical daughter cells is: Replication Meiosis Mitosis Fertilization 147 / 200The main hormone for growth in children is: Insulin GH (Growth Hormone) Thyroxine Testosterone 148 / 200In the lac operon of E. coli, lactose acts as a(n): Repressor Inducer Inhibitor Corepressor 149 / 200DNA replication occurs during which phase of the cell cycle? G2 phase M phase G1 phase S phase 150 / 200 In photosynthesis, the light-dependent reactions take place in the: Cytoplasm Stroma Inner mitochondrial membrane Thylakoid membranes 151 / 200Which part of the human brain is responsible for coordinating voluntary movements and maintaining posture and balance? Thalamus Medulla oblongata Cerebrum Cerebellum 152 / 200The human digestive system begins in the: Small intestine Mouth Esophagus Stomach 153 / 200In humans, the tube that connects the kidney to the urinary bladder is the: Ureter Collecting duct Nephron Urethra 154 / 200Which of these is a density-dependent limiting factor in population ecology? Volcanic eruption Hurricane Earthquake Competition 155 / 200Anticodons are present on: mRNA DNA tRNA rRNA 156 / 200The enzyme pepsin, which begins protein digestion in the stomach, is secreted in its inactive form called: Chymotrypsin Prolipase Pepsinogen Trypsin 157 / 200Which blood type is known as the universal donor? AB O A B 158 / 200Which of the following is NOT a function of the liver? Detoxification of drugs Storage of glycogen Production of insulin Production of bile 159 / 200Which organ is responsible for filtering blood and producing urine? Spleen Liver Kidney Pancreas 160 / 200Which blood cells are responsible for carrying oxygen? Plasma Platelets Red blood cells White blood cells 161 / 200The primary electron acceptor in Photosystem II (PSII) is: Cytochrome complex NADP+ Pheophytin Ferredoxin 162 / 200The process by which organisms maintain a stable internal environment is called: Homeostasis Metabolism Evolution Adaptation 163 / 200In the Hardy-Weinberg principle, which condition is NOT required for a population to be in genetic equilibrium? Non-random mating No natural selection No mutations A very large population size 164 / 200Mendel is known as the father of: Microbiology Genetics Evolution Ecology 165 / 200 A child is diagnosed with a genetic disorder characterized by a buildup of phenylalanine in the body due to a defective enzyme. This disorder is: Tay-Sachs disease Alkaptonuria Cystic Fibrosis Phenylketonuria (PKU) 166 / 200Which of the following is a function of the liver? Digestion of proteins Storage of glycogen Production of insulin Filtration of blood 167 / 200A plant with the genotype TtYy (where T=tall, t=short, Y=yellow seeds, y=green seeds) is self-crossed. What proportion of the offspring will be tall with green seeds? 3/4 1/16 9/16 3/16 168 / 200Which component of blood is responsible for carrying oxygen? Plasma Platelets Red Blood Cells White Blood Cells 169 / 200In humans, the number of chromosomes in a somatic cell is: 23 56 48 46 170 / 200Which of the following conveys the longest-lasting immunity to an infectious agent? Artificially acquired passive immunity Naturally acquired active immunity Naturally acquired passive immunity None of these 171 / 200Which of the following is a correct pathway for the flow of blood in the human heart? Right Ventricle → Left Atrium → Aorta Left Atrium → Left Ventricle → Pulmonary Vein Right Atrium → Right Ventricle → Pulmonary Artery Left Ventricle → Right Atrium → Vena Cava 172 / 200 Which organelle is known as the "powerhouse of the cell"? Golgi apparatus Nucleus Mitochondrion Ribosome 173 / 200Which hormone regulates blood sugar levels? Insulin Adrenaline Thyroxine Estrogen 174 / 200 The human heart has how many chambers? 4 2 3 1 175 / 200The process by which plants lose water vapor through their leaves is: Transpiration Evaporation Condensation Precipitation 176 / 200Which of the following is an example of a sex-linked recessive disorder? Cystic Fibrosis Sickle cell anemia Huntington's disease Haemophilia 177 / 200Which of the following is a sex-linked disorder? Hemophilia Down syndrome Turner syndrome Klinefelter syndrome 178 / 200Which of the following statements about the Krebs cycle is correct? It produces the majority of ATP in cellular respiration It directly requires oxygen It converts glucose to pyruvate It occurs in the cytoplasm 179 / 200Double fertilization is a characteristic of: Pteridophytes Gymnosperms Bryophytes Angiosperms 180 / 200The process of converting light energy into chemical energy occurs during: Digestion Transpiration Photosynthesis Respiration 181 / 200The part of the human ear that converts sound vibrations into electrical signals is the: Auditory Nerve Tympanic Membrane Cochlea Malleus, Incus, and Stapes 182 / 200 In a dihybrid cross (AaBb x AaBb), what is the phenotypic ratio in the F2 generation if the genes assort independently? 9:3:3:1 1:1:1:1 3:1 1:2:1 183 / 200Which type of junction creates a tight seal between adjacent animal cells, preventing leakage of extracellular fluid? Tight junction Plasmodesmata Desmosome Gap junction 184 / 200Which of the following is an example of analogous structures? Whale flipper and human arm Human arm and bat wing Turtle leg and horse leg Bird wing and butterfly wing 185 / 200The gradual and fairly predictable change in the species composition of a given area is called: Adaptation Biodiversity Evolution Ecological succession 186 / 200Which of these is NOT a part of the digestive system? Stomach Liver Small intestine Kidney 187 / 200Hyposecretion of ADH causes: Diabetes insipidus Diabetes mellitus Acromegaly Goitre 188 / 200Myelin sheath, which speeds up nerve impulse conduction, is produced by which cells in the central nervous system? Astrocytes Oligodendrocytes Motor neurons Schwann cells 189 / 200Which blood cells are responsible for carrying oxygen? Platelets Plasma White blood cells Red blood cells 190 / 200Which of the following is a communicable disease? Cancer Heart disease Tuberculosis Diabetes 191 / 200Which hormone causes ovulation? Progesterone Estrogen LH FSH 192 / 200The part of the neuron that receives signals from other neurons is the: Myelin sheath Axon Dendrite Cell body 193 / 200During DNA replication, the enzyme that joins Okazaki fragments on the lagging strand is: DNA polymerase DNA ligase Primase Helicase 194 / 200The structure formed by the wrapping of an axon by Schwann cells is called: Node of Ranvier Myelin Sheath Synaptic Cleft Neuromuscular Junction 195 / 200The primary function of the Calvin cycle is to: Produce oxygen Split water molecules Capture light energy Synthesize simple sugars 196 / 200The process by which populations change over time through genetic variation and natural selection is called: Evolution Mutation Speciation Adaptation 197 / 200Haemophilia is a: Sex-linked disorder Autosomal disorder Infectious disease Chromosomal deletion 198 / 200In the human respiratory system, gas exchange occurs in the: Trachea Bronchi Alveoli Bronchioles 199 / 200During the contraction of a sarcomere in muscle fibers, which of the following regions shortens? The A band The H zone Both the I band and the H zone The I band 200 / 200 In a DNA molecule, if the sequence of one strand is 5'-ATGCGT-3', the complementary strand will be: 3'-ATGCGT-5' 3'-TACGCA-5' 5'-ACGCAT-3' 5'-TACGCA-3' Your score isThe average score is 74% 0% Restart quiz