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: if fossils of a water animal or plant are found in a place then that place used to be covered by water in the past.
Sentence2: if remains of prehistoric life are found in a place then that place used to be covered by water.
[A]: be

[Q]: Sentence1: Ozone depletion results in higher levels of UV radiation reaching Earth.
Sentence2: less ozone means more ultraviolet light.
[A]: Ozone

[Q]: Sentence1: Vesicle transport requires energy, so it is also a form of active transport.
Sentence2: Active transport involves movement of substances against a chemical gradient.
[A]:
active