A marine biologist is designing an empirical investigation to study the effect of ocean acidification on the shell thickness of a specific bivalve species (Mytilus edulis\textit{Mytilus edulis}Mytilus edulis).
Which one of the following is a fundamental requirement for the biologist's hypothesis to be considered scientifically testable?
The hypothesis must be formulated as a directional prediction, as non-directional predictions are not empirically testable.
The variables within the hypothesis must be operationalised into specific, measurable parameters.
The hypothesis must be supported by a substantial body of pre-existing, peer-reviewed scientific literature.
The hypothesis must explicitly contain the literal terms 'independent variable' and 'dependent variable' within its text.
689 exam-style questions on AQA A Level Psychology Scientific processes. Each one has a worked solution and a mark scheme showing where the marks go.