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Paul investigated the effect of sunlight on the growth of the shoots of four plants - Edexcel - GCSE Biology - Question 3 - 2016 - Paper 1
Question 3
Paul investigated the effect of sunlight on the growth of the shoots of four plants. The shoots were treated in the following way. Shoot A had no changes made to it.... show full transcript
Worked Solution & Example Answer:Paul investigated the effect of sunlight on the growth of the shoots of four plants - Edexcel - GCSE Biology - Question 3 - 2016 - Paper 1
Step 1
Complete the sentence by putting a cross (✗) in the box next to your answer.
Answer
The growth response shown by shoot A and shoot D is an example of D positive phototropism. This response indicates that shoot D, which was clear-capped and allowed light to penetrate, displayed positive phototropic growth towards the light source, while shoot A, which was untreated, also grew in the same fashion.
Step 2
(b) Explain why certain herbicides are used to control weeds.
Answer
Herbicides are designed to act specifically on broad-leaf plants, effectively causing their overgrowth and subsequent death. This is primarily due to cell elongation and thinning of the cell wall, creating a lack of support for the affected weeds. By targeting only these species, herbicides help to maintain healthy crops while controlling unwanted vegetation.
Step 3