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: Lancelet larvae are free-swimming. 
Sentence2: some larvae lack a hardened backbone.
answer:
larvae


question:
Sentence1: Microbes are also called bacteria or microorganisms. 
Sentence2: Disease-causing bacteria have a negative impact on the body.
answer:
bacteria


question:
Sentence1: an image in a mirror is formed by reflecting light. 
Sentence2: Water is essentially a perfect mirror, reflecting colors almost unchanged.
answer:

mirror