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OpenStem
@openstem · Joined Jul 2026
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Quiz5 questions
Which part of the brain acts as the body's temperature "thermostat"?
AThe cerebellumBThe hypothalamusCThe pituitary glandDThe medulla oblongata
Biology · L3 · Homeostasis and Thermoregulation Quiz
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Biology · L3 · Homeostasis and Thermoregulation QuizQuiz5 questions
Which macronutrient provides about 9 kilocalories per gram — roughly double the energy of the other two?
ACarbohydrateBProteinCFatDVitamin
Biology · L3 · Human Nutrition Quiz
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Biology · L3 · Human Nutrition QuizQuiz5 questions
What determines a person's ABO blood type?
AThe number of red blood cells in their bodyBWhich antigens (A, B, both, or neither) are present on their red blood cellsCThe color of their blood plasmaDHow quickly their blood clots
Biology · L3 · Blood Types and Transfusion Quiz
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Biology · L3 · Blood Types and Transfusion QuizQuiz5 questions
Which layer of the skin is avascular (has no blood vessels of its own) and is made mostly of keratinocytes?
AHypodermisBDermisCEpidermisDSubcutaneous layer
Biology · L3 · The Integumentary System Quiz
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Biology · L3 · The Integumentary System QuizQuiz5 questions
What is the primary role of the lymphatic system in fluid balance?
ATo pump blood toward the lungsBTo return excess tissue fluid to the bloodstreamCTo produce new red blood cellsDTo regulate body temperature
Biology · L3 · The Lymphatic System
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Biology · L3 · The Lymphatic SystemQuiz5 questions
Sickle cell anemia is caused by a mutation affecting which protein?
AInsulinBHemoglobinCCollagenDKeratin
Biology · L3 · Genetic Disorders Quiz
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Biology · L3 · Genetic Disorders QuizQuiz5 questions
Which of these is a physical (structural) defense rather than a chemical defense?
ANicotine stored in tobacco leavesBCapsaicin in chili pepper fruitCSharp spines on a cactusDBitter alkaloids in foxglove leaves
Biology · L3 · Plant Defenses and Adaptations Quiz
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Biology · L3 · Plant Defenses and Adaptations QuizQuiz5 questions
A newly hatched sea turtle crawls toward the ocean immediately after hatching, without any parent present to teach it. This is an example of what kind of behavior?
ALearned behaviorBInnate (instinctive) behaviorCOperant conditioningDHabituation
Biology · L3 · Animal Behavior: Instinct and Learning
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Biology · L3 · Animal Behavior: Instinct and LearningQuiz5 questions
Which of these best describes a genetically modified organism (GMO)?
AAn organism whose genes have been deliberately changed by scientists to give it a new traitBAny organism that has been selectively bred by farmers over many generationsCAn organism that developed a random new mutation entirely on its ownDAn organism that has been cloned from an adult body cell
Biology · L3 · Cloning and GMOs Quiz
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Biology · L3 · Cloning and GMOs QuizQuiz5 questions
Which combination of changes narrows the airways during an asthma attack?
AInflammation, bronchoconstriction, and extra mucusBDestroyed cilia and broken-down alveolar wallsCFluid filling the alveoliDCartilage rings collapsing in the trachea
Biology · L3 · Respiratory Disorders Quiz
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Biology · L3 · Respiratory Disorders QuizQuiz5 questions
Which vertebrate class has a heart with just two chambers — one atrium and one ventricle?
AFishBAmphibiansCReptilesDMammals
Biology · L3 · Comparative Vertebrate Body Plans Quiz
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Biology · L3 · Comparative Vertebrate Body Plans QuizQuiz5 questions
A wildlife population shows differences in coat color, size, and disease resistance among its individual members. Which level of biodiversity does this describe?
AEcosystem diversityBGenetic diversityCSpecies diversityDHabitat diversity
Biology · L3 · Biodiversity and Conservation Quiz
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Biology · L3 · Biodiversity and Conservation QuizQuiz5 questions
What is a mycelium?
AA single reproductive spore released by a fungusBThe branching mass of hyphae that forms the main feeding body of a fungusCThe cap of a mushroom that releases sporesDA mutualistic partnership between a fungus and a plant root
Biology · L3 · Fungi: Decomposers, Partners, and Pathogens
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Biology · L3 · Fungi: Decomposers, Partners, and PathogensQuiz5 questions
An organism that thrives in very hot environments, such as a deep-sea hydrothermal vent, is best described as a:
AHalophileBThermophileCPsychrophileDAlkaliphile
Biology · L3 · Extremophiles: Life at the Edges Quiz
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Biology · L3 · Extremophiles: Life at the Edges QuizQuiz5 questions
What observation led Edward Jenner to investigate cowpox as a possible protection against smallpox?
AMilkmaids who had caught cowpox rarely seemed to catch smallpoxBA vaccine had already been proven to work against a different diseaseCCowpox and smallpox were known to be caused by the exact same virusDCows were observed to be immune to all human diseases
Biology · L3 · Vaccine History and Herd Immunity Quiz
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Biology · L3 · Vaccine History and Herd Immunity QuizQuiz5 questions
Which statement best defines coevolution?
AOne species adapting to a fixed physical environment, like temperature or rainfallBTwo species exerting reciprocal selection pressure on each other over generations, so a change in one favors a counter-change in the otherCA single species evolving in complete isolation from all other speciesDA sudden, one-time genetic mutation that appears in two species at once
Biology · L3 · Coevolution and Arms Races Quiz
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Biology · L3 · Coevolution and Arms Races QuizQuiz5 questions
What is turgor pressure?
APressure created when a plant cell's wall pulls away from its membraneBThe outward pressure of a cell's contents pushing against a rigid cell wall as water enters by osmosisCThe force roots exert while pulling water up from the soilDA pressure that only forms in animal cells placed in a hypotonic solution
Biology · L3 · Plant Water Relations Quiz
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Biology · L3 · Plant Water Relations QuizQuiz5 questions
Photoperiodism is best defined as a plant's response to:
ASoil temperatureBThe relative length of day and nightCWater availabilityDWind exposure
Biology · L3 · Photoperiodism Quiz
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Biology · L3 · Photoperiodism QuizQuiz5 questions
Magnetoreception refers to an animal's ability to:
ATaste changes in water salinityBSense Earth's magnetic fieldCSee ultraviolet light onlyDDetect barometric pressure
Biology · L3 · Animal Migration and Navigation Quiz
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Biology · L3 · Animal Migration and Navigation QuizQuiz5 questions
During prophase I, homologous chromosomes pair up tightly along their length and form a four-chromatid structure. What is this pairing process called?
AIndependent assortmentBSynapsisCCytokinesisDFertilization
Biology · L3 · Meiosis Mechanics Quiz
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Biology · L3 · Meiosis Mechanics QuizQuiz5 questions
Which plant hormone triggers stem elongation and helps break seed dormancy by activating enzymes that mobilize stored food?
AGibberellinsBEthyleneCCytokininsDAbscisic acid
Biology · L3 · Plant Hormones Beyond Auxin Quiz
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Biology · L3 · Plant Hormones Beyond Auxin QuizQuiz5 questions
Which type of endocytosis is best described as a white blood cell engulfing a whole bacterium?
APinocytosisBPhagocytosisCReceptor-mediated endocytosisDExocytosis
Biology · L3 · Endocytosis and Exocytosis Quiz
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Biology · L3 · Endocytosis and Exocytosis QuizQuiz5 questions
Which statement best describes where antibiotic resistance genes come from in a bacterial population?
AThe antibiotic itself creates the resistance trait in bacteria that are exposed to itBResistant variants already exist in the population before the antibiotic is ever applied, due to natural genetic variationCBacteria develop resistance only after several generations of direct exposure to a drugDResistance appears at random the moment a bacterium senses an antibiotic nearby
Biology · L3 · How Antibiotic Resistance Evolves Quiz
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Biology · L3 · How Antibiotic Resistance Evolves QuizQuiz5 questions
Which process converts unreactive atmospheric nitrogen gas (N2) into a usable form such as ammonia?
ANitrificationBNitrogen fixationCDenitrificationDAssimilation
Biology · L3 · The Nitrogen Cycle Quiz
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Biology · L3 · The Nitrogen Cycle QuizQuiz5 questions
Which receptor type detects the sound vibrations that reach the cochlea?
APhotoreceptorBChemoreceptorCMechanoreceptorDNociceptor
Biology · L3 · Sensory Receptor Types Quiz
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Biology · L3 · Sensory Receptor Types QuizQuiz5 questions
A hydra grows a small new individual as an outgrowth on its body, which later detaches. What is this process called?
AFragmentationBBuddingCParthenogenesisDSexual reproduction
Biology · L3 · Asexual vs. Sexual Reproduction Quiz
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Biology · L3 · Asexual vs. Sexual Reproduction QuizQuiz5 questions
Which type of ecological pyramid can never be inverted, under any circumstances?
APyramid of numbersBPyramid of biomassCPyramid of energyDAll three can be inverted
Biology · L3 · Ecological Pyramids Quiz
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Biology · L3 · Ecological Pyramids QuizQuiz5 questions
What is thigmotropism?
AGrowth toward a light sourceBGrowth response to touching a solid objectCGrowth toward a source of moistureDGrowth response to the pull of gravity
Biology · L3 · Thigmotropism and Hydrotropism Quiz
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Biology · L3 · Thigmotropism and Hydrotropism QuizQuiz5 questions
An animal whose body temperature rises and falls with its surroundings, and which warms itself mainly by basking in the sun, is best described as a:
AEndothermBEctothermCHomeotherm onlyDDecomposer
Biology · L3 · Animal Thermoregulation Strategies Quiz
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Biology · L3 · Animal Thermoregulation Strategies QuizQuiz5 questions
What is an allergen?
AA cell that produces antibodiesBA normally harmless substance that triggers an unnecessary immune responseCA protein the body makes to fight off its own cellsDA chemical released by mast cells
Biology · L3 · Allergies and Autoimmune Disease Quiz
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Biology · L3 · Allergies and Autoimmune Disease Quiz