A grower produces tomatoes using hydroponics. Which statement describes hydroponics?
growing plants in soil with extra fertiliser added to it each week
growing plants in a greenhouse that is heated by burning fuel
growing plants with their roots in a solution of mineral ions
growing plants that have had a gene from another species added
127 exam-style questions on OCR GCSE Biology 6.2 Feeding the human race, covering 6.2.1 Biological factors affecting food security, 6.2.2 Agricultural solutions to growing demand, 6.2.3 Selective breeding, 6.2.4 Genetic engineering, 6.2.5 Steps in genetic engineering, 6.2.6 Benefits and risks of gene technology in agriculture, and 6.2.7 Biotechnological solutions to growing demand. Each one has a worked solution and a mark scheme showing where the marks go.