TASK DEFINITION: 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.
PROBLEM: Sentence1: Most copepods feed on phytoplankton. 
Sentence2: most copepods feed on bacteria and algae that use sunlight to make food.

SOLUTION: copepods

PROBLEM: Sentence1: Lions live in social groups called prides. 
Sentence2: Chimpanzees live in social groups called communities.

SOLUTION: groups

PROBLEM: Sentence1: Mammals have a layer of fat under the skin to help insulate the body. 
Sentence2: Insulation is very important in a cold climate like Arkhangelsk.

SOLUTION:
insulate