A scientist investigates four substances, P, Q, R and S, found in germinating barley grains.
Which finding shows that one of the substances is a plant hormone?
S is a sugar that provides a substrate for respiration during germination
P is stored in the grain and is broken down into sugars during germination
Q is made by the barley plant and is used to build cell walls in the new shoot
R is made by the barley plant and changes the activity of target cells during germination
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.