Practice Test 18 - 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 runs up a flight of stairs and their body temperature rises above its usual level. In response, sweating increases, which cools the body and brings temperature back toward normal. Which type of feedback mechanism is this?
2. In a human body cell, about 2 meters of DNA (all chromosomes combined) must fit inside a nucleus that is only about 10 micrometers in diameter. Which description best explains how DNA is organized and packaged into chromosomes so it can fit in the nucleus?
3. A student observes a sample that contains many similar elongated cells that contract together to produce movement. The sample is not made of multiple different tissue types—just one main kind of working cell group. What level of biological organization is this sample most likely?
4. Himalayan rabbits all have the same genotype for a temperature-sensitive fur-color trait. A rabbit raised in a warm environment develops mostly white fur, but the same rabbit genotype raised in a colder environment develops dark fur on cooler body parts (ears, nose, feet). Which statement best explains this difference?
5. Identical twins (same genotype) are separated at birth. Twin 1 grows up with consistent access to nutritious food, while Twin 2 experiences long-term poor nutrition during childhood. As adults, Twin 1 is 178 cm tall and Twin 2 is 165 cm tall. Which explanation is most accurate?
6. In dogs, floppy ears (E) are dominant over pointed ears (e). A homozygous dominant dog is crossed with a heterozygous dog: $EE \times Ee$. What is the probability an offspring will have genotype $Ee$?
7. Two parents are both heterozygous (Tt) for a height trait where T = tall (dominant) and t = short (recessive). A Punnett square is used to show possible offspring genotypes. Which statement is correct about inheritance in this cross?
8. A population graph shows a J-shaped curve: it starts slowly and then becomes steeper and steeper, with no sign of leveling off. Which description best fits what the graph suggests about resources and limits?
9. A short mRNA segment is AUG-CCG-UAA (three codons). A deletion removes one nucleotide in the second codon, making the sequence AUG-CGU-AA… (the grouping into codons changes after the deletion). What is the most likely consequence for the protein?
10. A food chain is: grass (producer) → grasshopper (primary consumer) → frog (secondary consumer) → snake (tertiary consumer). If the frog has about 80 energy units available, about how much energy would be available to the snake according to the 10% rule?
11. A fish population has two phenotypes: striped and unstriped. In clear water, striped fish avoid predators better. Each generation, 70% of striped fish survive to reproduce, but only 35% of unstriped fish survive to reproduce. What is the best prediction about the striped phenotype frequency over time (assuming the trait is heritable)?
12. During transcription, a section of DNA unwinds and one strand serves as a template. RNA nucleotides then pair with the exposed DNA bases (using U instead of T), RNA polymerase builds the RNA strand, and the new RNA separates while the DNA re-zips. Which event happens immediately after RNA nucleotides base-pair with the DNA template strand?
13. A biologist measures the wing length (in mm) of 12 finches from the same island population: 12, 14, 14, 15, 16, 16, 17, 18, 18, 19, 20, 21 Which statement best describes the type of variation shown for wing length in this population?
14. A structure is described as being made of multiple tissue types (muscle tissue for pumping, connective tissue for support, and nervous tissue for control) that work together to move blood. What level of organization is being described?
15. A student says: "The model shows that chlorophyll creates energy for the plant." Which correction best matches the model?
16. A city's river has high levels of untreated sewage after heavy rain because stormwater and sewage share the same pipes, causing overflow. Two solutions are proposed: Solution A builds a larger treatment plant to handle overflow events. Solution B reduces stormwater entering pipes by adding green roofs, rain gardens, and permeable pavement across neighborhoods. Which statement best compares the solutions for long-term reduction of sewage pollution?
17. Which option correctly matches each process with its main reactants and products? Photosynthesis and cellular respiration are shown conceptually as opposite processes.
18. A lizard population includes individuals with high heat tolerance and low heat tolerance (heat tolerance is heritable). Over several decades, average summer temperatures rise due to climate change. Which statement best describes how natural selection would act on this variation?
19. A student says: "Because photosynthesis makes oxygen, plants do not need to do cellular respiration." Which option best corrects this statement while comparing the two processes?
20. A city wants to reduce air pollution that damages nearby forests (leaf injury and reduced growth). Two approaches are proposed: Approach A: Install scrubbers on factory smokestacks to remove pollutants before they enter the air. Approach B: Wash tree leaves with water trucks each week during the summer. Which approach is more effective at addressing the root cause of the forest damage?

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