Experiment: Plants of the same species were grown in soils containing different heavy metals (lead, mercury, arsenic). Root growth and leaf color were recorded after 2 weeks.Observation: Plants in lead and mercury had stunted roots and yellowing leaves; those in arsenic barely grew.Question: What is the most reasonable conclusion?
Correct answer: D. Heavy metals inhibit plant growth and disrupt chlorophyll production.
- A. All plants are unaffected by toxic metals.
- B. Lead and mercury improve water absorption in roots.
- C. Arsenic promotes healthy plant metabolism.
- D. Heavy metals inhibit plant growth and disrupt chlorophyll production.
Explanation
The correct answer is that heavy metals inhibit plant growth and disrupt chlorophyll production. This conclusion is supported by the observation of stunted roots and yellowing leaves in plants exposed to lead and mercury, as well as minimal growth in plants exposed to arsenic. The other options are incorrect because they do not align with the observed effects of heavy metals on the plants in the experiment.
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About Scientific Reasoning
Scientific reasoning evaluates hypotheses through observations, variables, controls, measurements and experimental results. Questions involve identifying independent and dependent variables, recognising a fair test, interpreting tables or graphs, distinguishing evidence from opinion, and deciding whether data supports, rejects or leaves a hypothesis unresolved.
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