A germinating pea is fixed in a holder so that its young shoot points vertically downwards. It is kept in darkness and photographed every hour for 24 hours.
Which time-lapse record shows a growth response to gravity?
the shoot gradually becomes longer and curves in different sideways directions
the shoot moves upright during the first hour without becoming longer
the shoot gradually becomes longer and continues growing vertically downwards
the shoot gradually becomes longer and its tip curves until it points upwards
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.