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2 - Living Organisms and Their Environment

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✅EvaluateQuestion 1 of 21

Which definition best describes an ecosystem?

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✅EvaluateQuestion 2 of 21

Which of the following is an ABIOTIC factor in a Caribbean lagoon?

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✅EvaluateQuestion 3 of 21

Which instrument measures dissolved oxygen (mg L⁻¹) in a school pond?

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✅EvaluateQuestion 4 of 21

Choose the correct sequence of ecological organisation from smallest to largest.

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✅EvaluateQuestion 5 of 21

Which statement correctly compares HABITAT and NICHE?

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✅EvaluateQuestion 6 of 21

What is the usual unit for measuring salinity during a mangrove field study?

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✅EvaluateQuestion 7 of 21

Which ecosystem is characterised by prop roots and fluctuating salinity?

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✅EvaluateQuestion 8 of 21

Which sampling method is MOST suitable to estimate grass cover along a 10 m school-field transect?

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✅EvaluateQuestion 9 of 21

At midday on a hot, still day, tilapia in a pond begin to gulp air. Which factor MOST likely caused this?

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✅EvaluateQuestion 10 of 21

Light intensity under a seagrape canopy is 1.5 × 10³ lux, while in full sun it is 2.0 × 10⁴ lux. Which outcome is MOST likely in the shade?

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✅EvaluateQuestion 11 of 21

“A doctor bird drinks nectar from hibiscus flowers at dawn.” This description refers to the bird’s:

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✅EvaluateQuestion 12 of 21

Which pairing is MOST accurate?

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✅EvaluateQuestion 13 of 21

Which statement best identifies a COMMUNITY on a limestone hillside?

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✅EvaluateQuestion 14 of 21

Morning DO = 7.0 mg L⁻¹, afternoon DO = 4.8 mg L⁻¹ in a small pond. Which is the BEST explanation?

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✅EvaluateQuestion 15 of 21

Three sites are surveyed for mangrove restoration: A: Salinity ~35 ppt (open sea); B: Salinity 5–25 ppt (tidal estuary); C: Salinity ~0 ppt (freshwater stream). Where will red mangrove seedlings MOST likely survive best?

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✅EvaluateQuestion 16 of 21

Counts of ghost crab holes along a 20 m transect from the waterline are: 0 m = 18, 5 m = 11, 10 m = 5, 15 m = 2, 20 m = 1. Which abiotic factor BEST explains the pattern?

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✅EvaluateQuestion 17 of 21

When testing the effect of SALINITY on mangrove seedling growth in a lab, which is the BEST controlled variable?

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✅EvaluateQuestion 18 of 21

If two species occupy the same habitat and identical niche, what is the most likely long-term outcome?

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✅EvaluateQuestion 19 of 21

Which statement about dissolved oxygen (DO) over a 24-hour cycle in a pond is MOST correct?

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✅EvaluateQuestion 20 of 21

A student records seawater pH = 6.5 using a meter. Which action is BEST before reporting?

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✅EvaluateQuestion 21 of 21

Turbidity near a river mouth is 80 NTU and seagrass is absent; offshore turbidity is 5 NTU with abundant seagrass. Which factor MOST limits seagrass near the river mouth?

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✅EvaluateQuestion 1 of 21

Which definition best describes an ecosystem?

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