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: an animal requires nutrients to grow and heal. 
Sentence2: Microbes can help an animal to grow and heal.
grow

Sentence1: Enveloped viruses make their own membranes. 
Sentence2: Some viruses make their own membranes.
make

Sentence1: tectonic plates being pushed together causes earthquakes. 
Sentence2: For example, an earthquake hits San Francisco.

earthquakes