Isotopes.............................
<h2><u><em>They provide goods and services that are economically and ecologically indispensable. Often called nurseries of the sea and they provide vital nesting and feeding habitats for many aquatic plants and animals</em></u></h2><h3><u><em>i hope this helps </em></u></h3>
A cell is the smallest LIVING unit in a body. An atom is the smallest "nonliving" unit.
The correct answer would be: B. I hope this helped!