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Practice Test 72 - High School Biology

20 questions. Answer them in any order, then submit to see your score and every explanation.

  1. A strawberry plant can produce seeds after pollination (pollen and egg fuse), and it can also produce new plants from runners that grow along the ground. Which option correctly matches each method with the type of reproduction and the expected genetic similarity of offspring?
  2. Two different mRNA molecules are translated on ribosomes in the cytoplasm. mRNA 1 has a different codon sequence than mRNA 2. What is the best prediction about the proteins produced?
  3. A cactus species shows variation in thorn length. In areas with many grazing animals, plants with long thorns lose fewer stems to herbivores than plants with short thorns. Which choice best explains how long thorns can increase fitness?
  4. In a musk ox herd, adults sometimes form a circle around calves when wolves approach. Which benefit of group living does this best illustrate?
  5. A tropical forest is cleared and replaced with a large cattle ranch. Within a few years, scientists observe fewer bird and insect species, and some animals that needed dense forest no longer live in the area. Which ecosystem impact is most directly caused by this human activity?
  6. A gene is a segment of DNA that contains instructions for making a protein. In pea plants, a height gene has two alleles: tall (T) and short (t), where T is dominant over t. Which statement best connects genotype to phenotype for this trait?
  7. During transcription of an insulin gene, the DNA in the nucleus unwinds, RNA nucleotides pair with the DNA template, and RNA polymerase builds an RNA strand that then separates. Which molecule is the direct product of transcription?
  8. A field ecosystem has the food chain: grasses (producer) → grasshopper (primary consumer) → frog (secondary consumer) → snake (tertiary consumer). If frogs have about 80 energy units available to them, about how much energy would you expect to be available to snakes, on average?
  9. A model uses arrows to show energy flow: [Sun] → [Light energy] → [Chloroplast] → [Glucose] → [Storage as starch] Which interpretation best matches the model's meaning of the arrow from glucose to storage as starch?
  10. A thermostat is set to 20°C. When the room cools to 18°C, the heater turns on; when the room warms to 21°C, the heater turns off. Which statement best describes how this example relates to homeostasis in living things?
  11. A hydra can form a small outgrowth (a bud) that grows and then breaks off to live on its own. The new hydra has the same DNA as the parent hydra (except for rare mutations). Which option correctly identifies this reproduction type and a key genetic consequence?
  12. Two grasslands experience the same drought. Grassland 1 keeps similar plant cover and productivity during the drought. Grassland 2 loses much of its plant cover during the drought but regrows to its pre-drought condition within the next year. Which comparison is most accurate?
  13. A DNA "rung" in the double helix is made by two bases pairing across the two strands. Which pair is a correct DNA base pair?
  14. In humans, oxygen is brought into the body by breathing and delivered to cells by the blood. In aerobic cellular respiration, what happens to the carbon dioxide (CO2) produced by cells?
  15. A student claims: "If there were no mutations, sexual reproduction would still create brand-new alleles forever." Which statement best evaluates this claim? Context: Sexual reproduction shuffles alleles through meiosis (independent assortment and crossing over) and random fertilization.
  16. A simple energy table for an ecosystem is shown below. Assuming the 10% rule, what value should replace the question mark for secondary consumers? Trophic level energies (kcal): Producers = 90,000; Primary consumers = 9,000; Secondary consumers = ?; Tertiary consumers = 90
  17. Use the simplified carbon cycle diagram description below to answer the question. Diagram (boxes and arrows): - Box 1: Atmosphere (CO2_2) - Box 2: Plants (biomass) - Box 3: Animals (biomass) - Box 4: Decomposers/Soil organic matter Arrows (labeled processes): - Atmosphere (CO2_2) → Plants (photosynthesis) - Plants → Animals (feeding) - Plants → Atmosphere (respiration) - Animals → Atmosphere (respiration) - Plants → Decomposers/Soil (death & waste) - Animals → Decomposers/Soil (death & waste) - Decomposers/Soil → Atmosphere (decomposition/respiration) Which pathway correctly traces carbon moving from the atmosphere into organisms and then back to the atmosphere, following the arrow directions?
  18. Claim: Larger group size leads to lower per-individual predation ("safety in numbers"). Experiment: - Researchers created artificial groups of different sizes in identical outdoor pens. - Each pen had one predator introduced for a fixed time. Results (percent of individuals killed during the trial): - Group size 1: 30% killed - Group size 5: 18% killed - Group size 10: 12% killed - Group size 20: 10% killed Which choice best evaluates the strength of this evidence for the claim?
  19. A lab technician grows bacteria in a flask that contains enough of a key nutrient to support 8,000,000 bacterial cells. Each cell requires 2 units of the nutrient, and the flask contains 16,000,000 units total. Assuming the nutrient is the limiting factor, what is the carrying capacity KK (maximum sustainable number of cells) in the flask?
  20. A hydra can reproduce by budding: a small hydra grows from the parent's body and later breaks off. The new hydra has the same DNA as the parent (except for rare mutations). Which option best describes this?

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