Which condition is necessary for an experiment to yield useful data?

Answer;

-Similar results should be obtained when the experiment is repeated.

Explanation;

-A valid experiment is repeatable; when you repeat your experiment, it should yield the same results. It is also reproducible. Someone else should be able to perform your experiment and get the same results.

-If other scientists get different results, then you have overlooked one or more important parts of your experimental design, like a variable you didn't take into account that influences the outcome.

the statement is true

the transfer for conduction is the heat transfering from the liquid to the spoon

the transfer for convection is the heat rising from the liquid to the air

the transfer for radiation is the heat going through the sides of the cup and to the air

at least that is what i would do