Practice Test 10 - Middle School Life Science

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

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1. Sunlight is the main energy source for most ecosystems. Refer to the model: Sunlight → berry bush (producer) → mouse (consumer) → owl (consumer). The arrows show energy flow, not matter movement. Which prediction about energy availability is supported if sunlight decreases for several weeks?
2. A plant population shows variation in leaf wax: high-wax leaves or low-wax leaves. A drought lasts for several growing seasons. Scientists measured survival from seedling to adult for each trait. What evidence links trait variation to population change in this situation?
3. A population of insects has two wing patterns: spotted and solid. A student looks only at Generation 4 and says, "This population evolved because most insects are spotted." Evolutionary change can be measured by shifts in trait frequency. Data (out of 100 insects each generation): - Generation 1: 90 spotted, 10 solid - Generation 2: 70 spotted, 30 solid - Generation 3: 55 spotted, 45 solid - Generation 4: 40 spotted, 60 solid Which claim about evolution is incorrect?
4. A simplified model shows instruction flow: "Gene (instructions) → Protein (does a job)." The model states: "Genes provide instructions for proteins." Which statement describes how genes relate to proteins?
5. A simplified model shows how photosynthesis adds matter to a plant. In the model, the arrow labeled energy input is "sunlight." Two arrows labeled matter enters point into the plant from "carbon dioxide in air" and "water in soil." The model labels that incoming matter ends up as "new plant material (leaves, stems, roots)." Which source provides matter to the plant, based on evidence from the model? Choose ONE.
6. Use the organism model to answer the question. The model shows a snail with two labeled systems: Digestive system and Muscular system (foot muscle). Arrows show food entering the digestive system, and arrows show nutrients moving from the digestive system to the foot muscle. The model indicates the snail's function of moving depends on interaction between systems. Which statement about system interaction is supported by the model?
7. A population of beetles lives in the same field for many generations. Beetles can have either a striped shell or a solid shell. Evolutionary change can be measured by shifts in trait frequency (the proportion of individuals with a trait) across generations. Trait frequency data: - Generation 1: 20 out of 100 are striped - Generation 3: 35 out of 100 are striped - Generation 5: 60 out of 100 are striped Which statement about evolutionary change is supported by the data?
8. Refer to the cell model shown. A student says, "Since the nucleus is the biggest part in the model, it must make the cell's energy." Which statement is supported by the model instead? Remember: size in a model does not always mean importance, and structure relates to function.
9. Two groups of the same breed of rabbits have different inherited traits affecting body size: Line L (larger-size trait) and Line S (smaller-size trait). They are raised for 12 weeks in two environments: High-protein diet and Standard diet. Evidence of average mass at 12 weeks: - High-protein: Line L = 2.6 kg, Line S = 2.1 kg - Standard: Line L = 2.2 kg, Line S = 1.9 kg What evidence shows an interaction between genes and environment affecting growth?​
10. A diagram shows an ant on the ground following a dashed trail labeled "sugar solution." The trail is marked with small droplets and faint wavy lines labeled "chemicals." Nearby, a flashlight shines on a different area of the ground. The stimuli originate outside the ant, and organisms detect different types of stimuli. Which stimulus is present in the environment?
11. A model states: "Genes provide instructions for proteins." In the model, an arrow labeled "instructions" goes from Gene A to Protein A. What evidence shows instruction flow in this model?
12. A pond has a baseline population of algae-eating snails that has stayed about the same for several months. In early spring, runoff adds extra fertilizer to the pond, and a student records that algae coverage increases for several weeks afterward. Based on this evidence and the change in resources, which prediction about the snail population over time is best supported (before vs. after the fertilizer runoff)? Remember that population changes can be predicted from evidence, but predictions are not certainties.
13. A student compares two inherited strains of fruit flies (Strain A and Strain B). Both strains are raised in the same incubator with the same temperature, same food, same cage size, and the same number of flies per cage. After 10 days, the student records the average body length. Which statement about genetics and growth is correct based on the evidence?
14. A simplified model shows two parent turtles: Parent X has a dark shell and short tail; Parent Y has a light shell and long tail. The offspring include turtles with different shell shades and different tail lengths, and the model states that sexual reproduction produces variation among offspring. Which statement about the offspring is supported by the model?
15. Ecosystem changes can affect populations. A pond was measured before and after a fertilizer spill increased nutrients in the water. Use the population data over time to choose 2–3 statements supported by the data. Data (average per sample): - Baseline condition (Week 0, before spill): Algae level 2 (low), Daphnia (water fleas) 40, Small fish 18 - Changed condition (Week 2): Algae level 8 (high), Daphnia 15, Small fish 20 - Week 6: Algae level 6, Daphnia 22, Small fish 12 Which statement about ecosystem change is supported by the data?
16. Ecosystem model: In a desert, cactus provide nectar and bat pollinators transfer pollen between cactus flowers. A late frost damages many cactus flower buds. Counts show fewer open flowers and fewer bat visits to cactus patches. Which prediction about the interaction outcome is supported by the evidence and environmental condition?
17. Two simplified models describe reproduction in a small insect. In the asexual model, 1 parent produces offspring that match the parent closely. In the sexual model, 2 parents produce offspring that are not all the same. A student says, "Because sexual reproduction has two parents, the offspring will always be completely different from each other." Which statement about reproduction type is correct, using evidence from both models?
18. Model: Proteins influence traits by affecting cell processes. In a snail, Protein F helps build a hard shell layer. A change in Protein F structure makes the shell-building process less effective. Evidence: Snails with changed Protein F had shells that cracked under lower force in a pressure test, but their shell color varied widely in both groups. Which statement about proteins and traits is supported by the evidence and model?
19. A rock column has 7 fossil layers, ordered oldest to youngest: Layer 1–Layer 7. Fossils found: Layer 1: crinoid. Layer 2: crinoid, fish bone. Layer 3: fish bone. Layer 4: fish bone. Layer 5: fish bone, turtle shell. Layer 6: turtle shell. Layer 7: turtle shell. Fossils provide evidence of extinction and appearance because they show when organisms are present or absent over time. Which prediction about fossil presence is most supported for a new layer (Layer 8) that formed after Layer 7 in the same location?
20. A museum display shows a sequence of fossils of ancient whales. Older fossils have small hind limb bones connected to the pelvis; younger fossils have much smaller hind limb bones; modern whales have tiny pelvis and hind limb remnants not used for walking. Which evidence suggests common ancestry between whales and land mammals? Choose the option that uses inherited structures and comparison across time.

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