Question

practice it! which of the following is not an example of an experimental investigation? testing the effect of temperature on old growth. recording when frogs jump most often. testing the amount of water on plant growth. testing techniques for drying smoothing cement.

Explanation:

An experimental investigation involves manipulating a variable to observe its effect. Testing the effect of temperature on old growth (manipulating temperature), testing the amount of water on plant growth (manipulating water amount), and testing techniques for drying smoothing cement (manipulating drying techniques) all involve variable manipulation. Recording when frogs jump most often is just observational data collection without variable manipulation.

Answer:

Recording when frogs jump most often.