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 there is sun, there is sunlight, there is day. 
Sentence2: Energy enters ecosystems from the sun.

A: sun
****
Q: Sentence1: waxy leaves are used for storing water by some plants. 
Sentence2: waxy leaves are used for water conservation by some plants.

A: leaves
****
Q: Sentence1: Basalts are volcanic, micro-crystalline rock. 
Sentence2: Breaking down basalt from larger into smaller pieces by weather is weathering.

A:
Basalts
****