Practice Test 81 - High School Biology

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

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1. Two different mRNA molecules are translated by ribosomes in the same cell. They have different base sequences. Which outcome is most likely?
2. A student describes the stomach as a structure that contains muscle tissue (for churning), epithelial tissue (lining), and nervous tissue (control). Which level of organization is the stomach?
3. If one DNA strand contains the base guanine (G) at a certain position, which base must be across from it on the other strand?​
4. Two students propose models for an indoor plant kept in a closed classroom overnight (no new air exchange), then exposed to sunlight the next day. Which model is more complete for showing that matter cycles between photosynthesis and respiration while energy flows one-way?
5. A plant species shows heritable variation in root depth (shallow vs. deep). A multi-year drought lowers the water table so that surface soil becomes very dry. Which root type would natural selection most likely favor during the drought?
6. A student draws a model with two boxes labeled Photosynthesis and Cellular Respiration. They want arrows that correctly show matter cycling (CO2, H2O, O2, glucose) between the boxes and a separate set of arrows for energy flow. Which set of arrows is correct?
7. A teacher shows two arrows patterns on the board: 1) A circular loop connecting photosynthesis and cellular respiration. 2) A straight arrow from Sun to heat. Which pairing of labels correctly matches these arrow patterns to what they represent in an ecosystem model?
8. An endangered frog species has about 60 adults left in the wild. The main threats are (1) loss of breeding ponds due to land drainage and (2) a fungal disease that kills tadpoles. A plan proposes captive breeding in a zoo and releasing frogs back into the same area without changing habitat conditions. Which evaluation best explains the limitation of this plan?
9. A student says, "Polymers form when monomers just stick together without any chemical change." Which correction best explains how monomers like glucose become polymers like cellulose?​
10. In pea plants, tall stems (T) are dominant to short stems (t). Two tall plants are crossed and produce 80 offspring: 61 tall and 19 short (about a 3:1 ratio). Which inheritance pattern and parent genotypes best explain the data?
11. Which statement correctly describes what a single chromosome is made of (in a typical human cell)?
12. A fish population was sampled for average body mass before and after an invasive predator arrived. Year → mean body mass (g): - 2000: 120 g - 2002: 118 g - 2004: 121 g - 2006: 119 g - 2008: 95 g (predator established by this year) - 2010: 88 g - 2012: 84 g Which statement best describes the trend direction and magnitude?
13. In mice, black fur (B) is dominant over brown fur (b). Two heterozygous mice are crossed: $Bb \times Bb$. What is the probability that an offspring will have genotype $Bb$?​
14. After a meal, blood glucose rises above normal. The body responds by releasing insulin, which helps cells take up glucose so blood glucose decreases back toward normal. Classify this feedback mechanism.
15. A lizard species lives on rocky slopes. After a new hiking trail is built, many rocks are removed and fewer crevices remain for lizards to hide from heat and predators. Over the next year, fewer young lizards survive to adulthood. Which limiting factor most likely caused the population to decline?
16. During photosynthesis, plants use CO2 and H2O to build glucose. Which statement best describes the energy transformation involved?
17. Two students have the same genotype for muscle-building potential (assume they are identical twins). One follows a strength-training program for a year; the other does not exercise. After a year, the exercising twin has larger muscles. Which statement best describes the relationship among genotype, environment, and phenotype here?
18. Two animals (a dolphin and a shark) have similarly shaped fins for swimming, but their internal structures differ: the dolphin fin contains bones similar to a mammal forelimb, while the shark fin has a different internal structure. Which statement best explains what this comparison shows about evidence for evolution?
19. A researcher graphs the frequency of a virus variant (Variant N) in a city over 6 months. Month: 1, 2, 3, 4, 5, 6 Variant N frequency: 5%, 9%, 21%, 44%, 68%, 82% Which statement best describes the evolutionary change shown?
20. Two processes are described: Process 1: A variable rises above normal, and the body triggers a response that makes the variable decrease back toward normal. Process 2: A change begins, and the response makes that change even larger, continuing until a clear endpoint. Which statement correctly classifies Process 1 and Process 2?

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