The magnetite, iron-sulfide, puritite, and possible gregite particles inside the carbonate globules are chemically, structurally and morphologically similar to particles produced by bacteria on Earth. The extremely small single celled structures resemble the microscopic fossils of the tiniest bacteria found on Earth. A few of the elongate forms appear to be segmented. In the state of Washington,drill cores a couple of kilometers deep in the Columbia River basalts show subterranean, subsurface bacteria, and some of them are these very small kind of bacteria. Similar textures containing ovoids have been found on the surface of calcite concretions grown from Pleistocene ground water in southern Italy, where they are interpreted as nannobacteria that have assisted the calcite precipitation.
Liquid water is eddential for all known biology.
There is no good evidence as yet of life cycles, or of cell division, or the presence of cell walls, if they are compartmentalized, or if they are composed of organic material The mere presence of organic matter by itself does not say it's part of life, because it is known that on Earth, prior to the origin of life, organic matter was synthesized non-biologically. There is not any one finding that leads us to believe that this is evidence of past life on Mars. Structures that could be microscopic fossils seem to support all of this. Every sand sized chip has most of these kinds of evidence in it. The relationship of all of these things in terms of location within a few hundred thousandths of an inch of one another - is the most compelling evidence.