A student places a gridded quadrat at sampling points at different distances from a woodland path and estimates the percentage cover of moss at each point.
Which of these is a control variable in this investigation?
the distance of each quadrat from the path
the percentage cover of moss in each quadrat
the person estimating the percentage cover
the soil moisture at each sampling point
109 exam-style questions on OCR GCSE Biology 6.1 Monitoring and maintaining the environment, covering 6.1.1 Field investigation of distribution and abundance, 6.1.2 Human interactions and biodiversity, 6.1.3 Maintaining biodiversity, and 6.1.4 Environmental change and distribution of organisms. Each one has a worked solution and a mark scheme showing where the marks go.