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: Sponges are filter feeders. 
Sentence2: Hawksbills feed primarily on filter feeders.
[A]: feeders


[Q]: Sentence1: Many plants respond to the days growing shorter in the fall by going dormant. 
Sentence2: Many plants respond to the autumnal equinox by going dormant.
[A]: Many


[Q]: Sentence1: Echinoderms lack respiratory and excretory systems. 
Sentence2: echinoids lack a respiratory system.
[A]:
respiratory