Equal numbers of young seedlings are placed horizontally. Half remain stationary. Half rotate slowly so that no side remains facing downwards. All are kept in darkness.
Which result would support a directional response to gravity?
stationary roots grow straight; rotating roots bend consistently
stationary roots grow straight; rotating roots stop growing entirely
stationary roots bend down; rotating roots show no consistent bend
stationary roots bend up; rotating roots show no consistent bend
105 exam-style questions on Edexcel GCSE Biology 6.3 Plant hormones, covering 6.3.1 Plant hormones and tropisms and 6.3.2 Commercial uses of plant hormones. Each one has a worked solution and a mark scheme showing where the marks go.