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: Clouds are one form of condensation. 
Sentence2: Clouds are one form of changing from a gas into a liquid by reducing heat energy.
answer:
Clouds


question:
Sentence1: optical tools are used for observing materials up close. 
Sentence2: Microscopes are set up for observation of smaller organisms.
answer:

observing