Answer:
testable questions are answer through observation or an experiment that provides evidence that the questions connects to the scientific concepts rather the opinion feelings
therefore the question can be tested through observation or experiment
Properties of a compound is completely different from their elements.
Water is composed by hydrogen and oxygen.
For example, the boiling point of oxygen is - 183 °C and hydrogen is - 253 °C, meanwhile, water has a boiling point of 100°C
Another example is when you put a burning wooden splint into oxygen, it burns more brightly. Put it in hydrogen, you may hear a "pop" sound, or even explode when large amount of hydrogen. But if u put a burning splint in water, it goes off.