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.

Input: Consider Input: Sentence1: Plants that shed their leaves seasonally each year are called deciduous plants. 
Sentence2: vines shed their leaves seasonally each year.

Output: each


Input: Consider Input: Sentence1: All chemical reactions require activation energy to get started. 
Sentence2: Catalysts lower the activation energy.

Output: activation


Input: Consider Input: Sentence1: cellular respiration is when a cell converts from oxygen and carbohydrates into carbon dioxide, water, and energy. 
Sentence2: a series of enzyme-mediated reactions is when a cell converts from oxygen and carbohydrates into carbon dioxide, water, and energy.


Output: carbohydrates