Skip to main content
Sign in Create a free account
Varsity Tutors
Sign in Sign up

Practice Test 11 - Middle School Life Science

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

  1. Ecosystem changes can affect populations. A lake was monitored before and after a dam was built upstream, lowering water flow into the lake. Data (water level and fish counts): - Baseline condition (Year 1): Water level 100 cm, Trout 42, Carp 12 - Changed condition (Year 2): Water level 80 cm, Trout 25, Carp 20 - Year 3: Water level 78 cm, Trout 18, Carp 24 Which evidence best links the ecosystem change to a population outcome?
  2. A model shows a young bird growing. In the before panel, small molecules are shown inside the bird's body. Arrows show these small molecules being linked and packed into thicker structures in the wing. In the after panel, the wing has more tissue than before. The model states: "Rearranged molecules support growth and repair." Which evidence from the model supports the idea that growth happens by rearranging molecules into larger structures (not just getting bigger in size)?
  3. Read the model description: Sunlight is the main energy source for most ecosystems. The arrows show energy flow and should not be confused with movement of matter. Model: Sunlight → seaweed (producer) → sea urchin (consumer) → sea otter (consumer). Which organism in the model receives energy indirectly from sunlight?
  4. A wetland is shrinking, reducing habitat for frogs and migrating birds. Evidence shows: draining nearby fields lowered the water table; restoring water flow by plugging drainage ditches increased wetland water levels and plant cover within 1 year; building a boardwalk for visitors reduces trampling in one area but does not change water levels; captive breeding of frogs increases frog numbers in tanks but released frogs have low survival if the wetland stays dry. Conservation choices: Option 1: Plug drainage ditches to restore water levels. Option 2: Build a boardwalk and add signs to keep visitors on trails. Option 3: Start a captive breeding and release program for frogs. Criteria: scientific effectiveness (restore wetland habitat), economic cost, and social feasibility. Constraints: landowners will allow ditch plugging only on public land sections; the budget can fund either ditch work or a boardwalk; staff time is limited. Which prediction would strengthen the justification for choosing Option 1, based on the evidence and constraints?
  5. Two simplified models show that reproduction type affects genetic outcomes. Asexual reproduction model: Parents involved: [1] Parent: ▣(checker) Offspring: ▣(checker) ▣(checker) ▣(checker) Sexual reproduction model: Parents involved: [2] Parents: ▣(checker) + ▢(blank) Offspring: ▣(checker) ▦(half) ▢(blank) Which statement about reproduction type is correct based on evidence from both models?
  6. Two birds (Parent 1 and Parent 2) reproduce sexually and have several chicks. The chicks show different beak lengths and different feather shades. The model states that sexual reproduction produces variation among offspring. Which statement about the chicks is supported by the evidence in the model?
  7. Two groups of the same kind of bean plant were grown for 3 weeks. Group 1 was watered every day. Group 2 was watered once a week. All other conditions were kept the same. The data show Group 1 grew 18 cm and Group 2 grew 6 cm. Based on this evidence, which environmental factor affects growth?
  8. Fossils were found in four rock layers at the same location. The layers are ordered from oldest to youngest as Layer 4, Layer 3, Layer 2, Layer 1. Fossils found: Layer 4: trilobite fossils only; Layer 3: trilobites and early fish fossils; Layer 2: fish fossils and amphibian fossils; Layer 1: amphibian fossils and reptile fossils. Which statement about how life has changed over long periods of time is best supported by these fossils?
  9. Refer to the organism model: Integumentary system (skin) forms a barrier (arrow showing protection) and helps keep water inside; this supports the Circulatory system by helping maintain stable conditions for blood flow. The model shows systems affect one another and organism function depends on system interaction. What happens if the integumentary system becomes damaged (more water loss) according to the model?
  10. A population of birds has two beak shapes: narrow and thick. Evolutionary change can be measured by shifts in trait frequency in a population across generations. In the same island population, the class recorded: Generation 1: 40 out of 80 narrow; 40 out of 80 thick Generation 2: 20 out of 80 narrow; 60 out of 80 thick Generation 3: 10 out of 80 narrow; 70 out of 80 thick Which statement about evolutionary change is supported by the evidence?
  11. Use the model to answer the question. The model shows food molecules (circles) inside an organism. When the food is used, energy is shown as starbursts labeled "energy released." Circles are matter and starbursts are energy. Which prediction about energy availability is supported by the model if the organism has no food molecules available to use?
  12. A lab used CRISPR gene editing to change a gene in tomato plants so the fruit ripens more slowly. In shipping tests, edited tomatoes had 30% fewer fruits spoiled during transport, so more tomatoes reached stores. But field trials also showed the edited plants produced 10% fewer seeds and attracted fewer pollinators than unedited plants. Technologies that select traits can have impacts and tradeoffs. Which statement about impacts is supported by the evidence?
  13. Model: A strong smell from vinegar (stimulus) reaches the nose (receptor). The nose detects the smell and sends a signal toward the brain. The brain processes signals from receptors. Which explanation describes how the brain processes signals according to the model?
  14. A class raises two inherited lines of guppies (Line X and Line Y) in separate tanks. The tanks are set to the same water temperature, same light schedule, same type and amount of food, and the same number of fish per tank. After 12 weeks, students measure average mass. What evidence shows a genetic influence on growth?​
  15. A park ranger tracked the same species of deer in the same park during two different summers. In Summer 1, there was a drought and only 2 watering ponds stayed full; the deer population counted at the end of summer was 36. In Summer 2, rainfall was higher and 7 watering ponds stayed full; the deer population counted at the end of summer was 58. Which explanation best describes the relationship between resources and population size using evidence (resources can limit population size)?
  16. A rabbit breeder selects only white-fur rabbits to be parents. Over 7 generations, the percent of rabbits with white fur increases from 30% to 90%. The breeder keeps the rabbits in the same housing and feeding conditions each generation. This shows humans can influence trait inheritance using technology. Which prediction about trait outcomes is supported if the breeder continues the same technology for several more generations?
  17. A tidepool crab population includes crabs with large claws and small claws. Evolutionary change can be measured by shifts in trait frequency (proportions) across generations. Data from the same population: Generation 1: 50 large, 50 small Generation 2: 60 large, 40 small Generation 3: 60 large, 40 small Generation 4: 60 large, 40 small Which statement about evolutionary change is supported by the evidence?
  18. Yeast were grown for 24 hours in containers with different amounts of sugar (a food resource). The graph shows the yeast population size over time. Which sugar level supports the most growth by 24 hours, based on the data and evidence? (Resources can limit or support growth.)
  19. Refer to the simplified cell model (interactions shown by arrows; not exact scale). Arrows show: Nucleus → Ribosomes → Proteins Proteins → Cell membrane Cell membrane → Cytoplasm Mitochondria → Energy → Proteins Choose the ONE unsupported claim.
  20. A student sets up a terrarium with a lizard on a rock. A heat lamp is positioned above one side (shown by red heat lines), and a cricket is in a small container releasing odor lines (labeled "cricket chemicals") on the other side. These stimuli come from outside the lizard, and organisms detect different types of stimuli. Which stimulus is present in the environment?

Practice tests