What does a scientist test when using a controlled experiment?(1 point)
Responses
a conclusion.
a conclusion.
several variables.
several variables.
a single variable.
a single variable.
a mass of information.
a single variable.
When is a hypothesis useful in science?(1 point)
Responses
When it can be proven incorrect.
When it can be proven incorrect.
When it is proven correct.
When it is proven correct.
When the explanation is already known.
When the explanation is already known.
When it can be tested.