A botanist uses black baffles to expose different regions of identical upright maize shoots to light from opposite directions. In group R, each shoot tip receives light from the left while the growing region below receives light from the right. In group S, each shoot tip receives light from the right while the growing region below receives light from the left.
Which pair of growth responses provides evidence that the tips determine the direction of bending?
group R bends left; group S bends left
group R grows straight; group S grows straight
group R bends left; group S bends right
group R bends right; group S bends left
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.