Which of the following is NOT a property of a mineral? naturally occurring, crystalline structure

inorganic substance

an ever changing unknown chemical composition (what it is made of)

always a solid; never a liquid or gas

You are given an electron micrograph of a bacterial cell. in the micrograph you can clearly see three thin layers of different densities surrounding the cell. based on the micrograph, you can infer that this cell is and would appear after application of the gram stain procedure. gram-negative / pink gram-positive / purple gram-positive / pink gram-negative / purple