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.

Sentence1: when a hemisphere is tilted away from the sun , that hemisphere receives less direct sunlight. 
Sentence2: Sunlight is delivered in small packets of energy called photons.
sunlight

Sentence1: Insects spread disease and destroy crops. 
Sentence2: Crops are plants that are grown for food or other uses.
crops

Sentence1: Cynodonts became more mammal-like as they continued to evolve. 
Sentence2: some therapsids became more mammal-like as they continued to evolve.

became