A student investigates whether the cuticle reduces pathogen entry. The student scratches leaves on one plant and leaves a second plant untreated. The two plants are different species.
Which change would best improve this comparison?
use plants of different species and expose both to the same pathogen
use plants of the same species and expose both to the same pathogen
use plants of the same species and expose each to a different pathogen
use plants of different species and expose each to a different pathogen
45 exam-style questions on Edexcel GCSE Biology 5.2 Plant and body defences, covering 5.2.1 Physical plant defences, 5.2.2 Chemical plant defences, 5.2.3 Detecting plant diseases, and 5.2.4 Human physical and chemical defences. Each one has a worked solution and a mark scheme showing where the marks go.