Given a scientific question and its correct answer, generate supporting facts for the answer. This supporting fact can be an explanation for the answer to the given question.

[EX Q]: Question: What do you call the electrons in the outermost energy level of an atom? Answer: valence electrons
[EX A]: Electrons in the outermost energy level of an atom are called valence electrons. They determine many of the properties of an atom, including how reactive it is.

[EX Q]: Question: What do ecosystems require constant inputs of? Answer: energy
[EX A]: Ecosystems require constant inputs of energy from sunlight or chemicals.

[EX Q]: Question: The presence of solute particles blocks some of the ability for liquid particles to do what? Answer: evaporate
[EX A]:
The presence of solute particles blocks some of the ability for liquid particles to evaporate. Thus, solutions of solid solutes typically have a lower vapor pressure than the pure solvent.