A grower has a broad-leaved crop containing narrow-leaved grass weeds. The grower considers spraying the field with a selective weed killer containing auxin. Which statement explains why this treatment would be unsuitable?
The crop and the grass weeds would grow larger after absorbing auxin, so neither type of plant would die.
The crop would absorb more auxin and enter uncontrolled growth, while the grass weeds would be largely unharmed.
The grass weeds would absorb more auxin and grow much faster, so they would shade out the crop.
The crop and the grass weeds would absorb equal amounts of auxin, causing both types of plant to die.
87 exam-style questions on AQA GCSE Biology 5.4 Plant hormones, covering 5.4.1 Control and coordination and 5.4.2 Use of plant hormones (HT only). Each one has a worked solution and a mark scheme showing where the marks go.