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: Interest in fossils is worldwide. 
Sentence2: paleontologists study something with worldwide interest.

SOLUTION: Interest

PROBLEM: Sentence1: plant reproduction requires pollination. 
Sentence2: Plant reproduction requires insects and hummingbirds.

SOLUTION: plant

PROBLEM: Sentence1: Some parasites kill their host, but most do not. 
Sentence2: All parasites are harmful to their host, but some are beneficial to humans.

SOLUTION:
host