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: Examples of gametes are ova and spermatozoa. 
Sentence2: fertilization of ova and spermatozoa produces a diploid zygote.

A: ova
****
Q: Sentence1: Dromaeosaurs are part of the theropod group of dinosaurs. 
Sentence2: Birds evolved from a group of bipedal dinosaurs that included Dromaeosaurs.

A: Dromaeosaurs
****
Q: Sentence1: transpiration is when water vapor moves from plants into the atmosphere. 
Sentence2: Chemicals can keep water vapor from moving into the atmosphere.

A:
atmosphere
****