Mistletoe takes water and mineral ions from a tree. During a drought, a tree with mistletoe grows less than a similar tree without mistletoe.
Which explanation links the relationship to the reduced growth?
Mutualism increases the mineral ions available to the tree.
Competition increases the water available to the mistletoe host.
Parasitism reduces the water available to the mistletoe host.
Predation reduces the mineral ions available to the parasite.
39 exam-style questions on Edexcel GCSE Biology 9.1 Ecosystems and interdependence, covering 9.1.1 Levels of organisation in ecosystems, 9.1.2 Abiotic and biotic factors, 9.1.3 Importance of interdependence, 9.1.4 Parasitism and mutualism, and 9.1.5 Determining number of organisms in an area. Each one has a worked solution and a mark scheme showing where the marks go.