instruction:
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.
question:
Sentence1: Roundworms make up the phylum Nematoda. 
Sentence2: Also, nematoda and rotifera are important groups contributing to soils.
answer:
Nematoda


question:
Sentence1: drought is when amount of precipitation decreases. 
Sentence2: Drought decreases the availability and abundance of the natural food supply.
answer:
drought


question:
Sentence1: Energy enters ecosystems in the form of sunlight or chemical compounds. 
Sentence2: Solar energy is clean energy .
answer:

Energy