Which statement about the use of independent variable in controlled experiment is correct

The facts collected from an experiment are written in the form of a hypothesis. 4. Which statement about the use of independent variables in controlled experiments is correct? (1) A different independent variable must be used each time an experiment is repeated. (2) The independent variables must involve time.

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they each offer a fresh glut of resources to the organisms that can arrive and exploit them. as individuals and new species continue to appear, they actively and passively alter the environment. competition for shared resources increases, local abiotic and biotic conditions shift, and the relative abundances of species change accordingly. the process is called ecological succession, and it is one of the earliest and most well-known concepts in ecology.

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