Practice Test 24 - High School Biology

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

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1. A student creates a simple model for oxygen delivery during exercise: Lungs → Blood → Muscles. What is the best improvement to make the model show system integration more clearly (while staying simple)?
2. Claim: A weed population in farm fields evolved resistance to Herbicide Q. Evidence: 1) In 2012, 10% of weeds survived Herbicide Q; in 2022, 12% survived. 2) In 2022, the farmer used a higher dose of Herbicide Q than in 2012. 3) In 2022, one weed plant survived even a very high dose and produced many seeds. 4) Lab tests show the resistance trait is heritable when resistant plants are crossed. Which evaluation is most accurate about whether the evidence supports the claim that the population evolved resistance?
3. In a certain animal, allele B is dominant to allele b. A homozygous dominant parent is crossed with a homozygous recessive parent: $BB \times bb$. What is the probability that an offspring will have genotype $Bb$?​
4. In a carbon cycle diagram, a box labeled "Decomposers/Soil organic matter" receives arrows from both Plants and Animals labeled "death & waste." It has an arrow pointing to "Atmosphere (CO$_2$)" labeled "decomposition/respiration." What role do decomposers play in this diagram?
5. In a plant species, tall (T) is dominant over short (t). A homozygous tall plant is crossed with a heterozygous tall plant: $TT \times Tt$. What is the probability that an offspring will be short?​
6. A new highway is built through a continuous forest, splitting it into several smaller patches separated by lanes of traffic and cleared roadside areas. Over time, a small mammal species is found in each patch, but individuals rarely move between patches. Which change is most likely to occur because of this habitat fragmentation?
7. Humans burn fossil fuels, releasing additional CO2 into the atmosphere. How does this relate to the carbon cycle in ecosystems?
8. A student says, "Photosynthesis makes energy for the plant." Which revision best matches the law of conservation of energy and the role of glucose in photosynthesis?
9. A flower-color gene provides instructions for making an enzyme that produces purple pigment. A functional allele (P) makes the enzyme; a nonfunctional allele (p) does not. Plants with PP or Pp are purple, and plants with pp are white. Which choice best describes how genes produce traits in this scenario?
10. DNA is often compared to a written language. In English, the words "CAT" and "TAC" use the same letters but mean different things because the letter order is different. Why does base order matter in DNA in a similar way?
11. A student compares two models of oxygen delivery during a jog. Model 1 includes only: "Respiratory → Muscular." Model 2 includes: "Respiratory → Circulatory → Muscular," and also shows "Muscular → Circulatory → Respiratory" for carbon dioxide return. Which statement best evaluates the models' usefulness for representing system integration?
12. In a simplified nitrogen cycle, atmospheric $N_2$ cannot be used directly by most plants. Which sequence best shows how nitrogen atoms can move from the atmosphere into animals and then back into the environment for reuse?
13. A growing town builds a new four-lane highway through a continuous forest. Over the next few years, biologists notice that some small mammal populations on opposite sides of the highway rarely mix, and each side shows lower genetic diversity than before the road was built. Which ecosystem impact best explains these observations?
14. In peas, yellow seeds (Y) are dominant over green seeds (y). A heterozygous plant is crossed with another heterozygous plant: $Yy \times Yy$. What is the probability that an offspring will have genotype yy?
15. Claim: A population of weeds evolved resistance to Herbicide Y. Evidence: 1) In 2010, 6% of weeds survived Herbicide Y; in 2018, 64% survived in the same fields. 2) The same fields received Herbicide Y every year from 2010 to 2018. 3) In 2018, some weeds were taller than others. 4) A greenhouse experiment grew seeds collected in 2010 and 2018 in identical conditions; seedlings from 2018 seeds were more likely to survive Herbicide Y. Which evaluation best supports the claim?
16. A pond ecosystem includes aquatic plants, snails, frogs, and herons. Snails eat aquatic plants; frogs eat snails; herons eat frogs. Which option correctly describes the consumer types in this chain?
17. Two people have similar genotypes related to muscle-building potential. Person A does regular strength training for a year, while Person B does not exercise. Person A has noticeably larger muscles. Which statement best explains this result?
18. Two populations of the same bacterial species are tracked for the frequency of an antibiotic-resistance allele $R$ over 12 weeks. Population A (no antibiotic used): Week 0: 1%, Week 4: 1%, Week 8: 2%, Week 12: 1% Population B (antibiotic used weekly): Week 0: 1%, Week 4: 14%, Week 8: 46%, Week 12: 73% Which statement best compares the two populations?
19. A student compares two models that explain oxygen delivery during a soccer game. Model 1: Only shows the circulatory system moving blood around the body. Model 2: Shows the respiratory system adding O2 to the blood and the circulatory system delivering O2 to muscles. Which statement best evaluates the models' ability to represent system integration?
20. Two students propose models for an ecosystem. Model A: CO2 + H2O → photosynthesis → glucose + O2 → cellular respiration → CO2 + H2O (matter loop shown). No energy arrows. Model B: CO2 + H2O ↔ photosynthesis ↔ glucose + O2 ↔ cellular respiration ↔ CO2 + H2O, plus Sun → photosynthesis → glucose → cellular respiration → heat. Which evaluation is correct?

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