Biology 0610 · IGCSE · Tropic responses

Tropic responses — practice question

2,4-D is a synthetic plant auxin used as a weedkiller. Researchers tested how effective different 2,4-D treatments were at controlling the weed Conyza canadensis in maize, Zea mays, fields. The findings are given in Table 5.1.
(a(i))[4]

Maize farmers who had been using treatment C were told by the researchers to move to treatment F. Discuss the benefits and drawbacks of changing to treatment F.

(a(ii))[2]

Suggest two factors that could reduce the effectiveness of 2,4-D.

(a(iii))[3]

Explain how 2,4-D acts as a weedkiller.

(b)[2]

Auxin makes the shoots of a plant grow away from gravity. State the name of this response.

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This 11-mark question has a full step-by-step worked solution and mark scheme. One marking point: Reduced (dry) mass

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