Ecosystems, Watersheds & Conservation — Chapter quiz · Science 6: Matter, Energy & Earth Systems, Grade 6

What can resource pathways and comparable records reveal about an ecosystem? Does the supplied buffer model change runoff and sediment under matched conditions, and what does that imply for a real watershed?

Problem 1

Which statement is scientifically accurate for Ecosystems, Habitats & Biomes?
  1. habitat: The setting and conditions an organism uses to live and obtain resources.
  2. More individuals always means more species.
  3. A biome label establishes identical conditions at every site.
  4. Every classroom model reproduces reality exactly.
Answer and explanation

habitat: The setting and conditions an organism uses to live and obtain resources.

The setting and conditions an organism uses to live and obtain resources. The shaded patch has greater recorded species richness, while the sunny patch has more recorded individuals. Neither measure alone proves a universally better habitat. Species identity, seasonal changes, detection, and the needs of a particular organism matter. These are illustrative patch records, not a survey of every forest.

Problem 2

A bird uses nesting cover in one patch and feeds in another. Must its habitat be one small fixed box?
Answer and explanation

No. Habitat use can span several features and locations. The study boundary should match the question rather than assume the organism never moves.

Compare the scientific meaning and reasoning after an independent attempt. A different accurate supported response can be correct; human review is required.

Problem 3

Which statement is scientifically accurate for Food Chains, Food Webs & Energy Flow?
  1. Food-web arrows always point from predator toward prey.
  2. producer: An organism that builds organic matter using an energy source rather than feeding on organic food.
  3. Every feeding transfer has exactly the same universal percentage.
  4. Every classroom model reproduces reality exactly.
Answer and explanation

producer: An organism that builds organic matter using an energy source rather than feeding on organic food.

An organism that builds organic matter using an energy source rather than feeding on organic food. The arrows show receiving organisms obtaining matter and energy from resources. 80 ÷ 800 = 10% in the stated biomass-transfer model, not a universal percentage. The second fish provides another feeding route, and the web lacks population sizes and rates; it cannot specify an exact future bird count.

Problem 4

A learner draws bird → fish to show that the bird eats fish. How should it be corrected under the course convention?
Answer and explanation

Draw fish → bird, showing the direction of matter and energy transferred through feeding. State the convention so the arrow can be interpreted.

Compare the scientific meaning and reasoning after an independent attempt. A different accurate supported response can be correct; human review is required.

Problem 5

Which statement is scientifically accurate for Cycling Matter Through Organisms & Environment?
  1. Recycling matter automatically recycles all usable energy.
  2. Decomposers make matter disappear.
  3. decomposition: Biological breakdown and transformation of organic material into other matter stores and forms.
  4. Every classroom model reproduces reality exactly.
Answer and explanation

decomposition: Biological breakdown and transformation of organic material into other matter stores and forms.

Biological breakdown and transformation of organic material into other matter stores and forms. Soil: 20 − 5 + 3 = 18 units. Plants: 8 + 5 − 2 = 11. Animals: 2 + 2 − 3 = 1. The total remains 30 units. These are simplified nutrient-account units, not a complete real decomposition pathway or energy total; actual stores and processes would be more detailed.

Problem 6

A student says decomposers return all the original food energy to plants. What distinction is missing?
Answer and explanation

Decomposition can return matter to usable nutrient pathways, but energy spreads through processes and thermal transfers. Plants still require an energy source such as sunlight.

Compare the scientific meaning and reasoning after an independent attempt. A different accurate supported response can be correct; human review is required.

Problem 7

Which statement is scientifically accurate for Human Impacts, Conservation & Tradeoffs?
  1. Every classroom model reproduces reality exactly.
  2. One favorable measure proves a proposal meets every goal.
  3. A before-and-after difference always isolates the intended action as its cause.
  4. conservation: Protecting or responsibly managing resources and ecological relationships through defined actions.
Answer and explanation

conservation: Protecting or responsibly managing resources and ecological relationships through defined actions.

Protecting or responsibly managing resources and ecological relationships through defined actions. Mean sediment is 20 g bare and 12 g buffered, a reduction of 8 g or 40% relative to the bare mean. The buffer fits the stated budget and merits a bounded further test. Tray records do not guarantee a 40% field reduction in all storms; scale, plant establishment, maintenance, and other outcomes need study.

Problem 8

A learner disagrees with a proposed conservation policy but accurately explains its mechanism and limitations. Must the science answer be marked wrong?
Answer and explanation

No. Evaluate scientific accuracy, evidence, and tradeoffs rather than agreement with a preferred policy or personal belief.

Compare the scientific meaning and reasoning after an independent attempt. A different accurate supported response can be correct; human review is required.

Problem 9

Which statement is scientifically accurate for Watersheds, Water Quality & Sampling Limits?
  1. watershed: An area whose drainage connects toward a common outlet under a defined landscape model.
  2. Clear-looking or filtered water is automatically safe to drink.
  3. One sample represents every place, season, and water-quality property.
  4. Every classroom model reproduces reality exactly.
Answer and explanation

watershed: An area whose drainage connects toward a common outlet under a defined landscape model.

An area whose drainage connects toward a common outlet under a defined landscape model. A’s mean dissolved oxygen is 8 mg/L; B’s is 5 mg/L. A has lower recorded turbidity under the stated method. These indicators support different physical/ecological comparisons, but the small record does not identify every cause, represent all seasons, or certify either water as safe to drink.

Problem 10

Friday’s water-quality entry is missing. May it be recorded as 0 mg/L oxygen?
Answer and explanation

No. Missing measurement is not measured zero. Preserve the absent entry and obtain a comparable record if the question requires it.

Compare the scientific meaning and reasoning after an independent attempt. A different accurate supported response can be correct; human review is required.

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