Generate an overlapping word between the given two sentences. When you find the overlapping words, they don't have to match exactly, e.g., "survival" and "survive" are valid overlapping words. Little words like "the" or "of" don't count! You must generate significant words which are not the stop words.

[Q]: Sentence1: Visible and invisible light is energy in the form of electromagnetic waves. 
Sentence2: Eyes are used for seeing animals by sensing electromagnetic waves.
[A]: electromagnetic


[Q]: Sentence1: a greenhouse is used to protect plants by keeping them warm. 
Sentence2: Flower size varies by plant.
[A]: plants


[Q]: Sentence1: condensing means changing from a gas into a liquid by reducing heat energy. 
Sentence2: Heat energy is measured in calories.
[A]:
energy