Living, dead or never alive

To be living, a thing must be made of cells and carry out all seven life processes at some point. To be dead, it must have been alive once. Things that were never made of cells are never alive.

Living	Dead (alive once)	Never alive
Basil, moss, a spider, yeast, the bacteria in live yoghurt, seeds (dormant), a pet dog	Logs, wooden tables, paper, cotton, leather, cooked prawns, a fallen leaf	Flames, water, ice, salt crystals, metal, glass, a phone, a plastic toy

Tricky ones. Fire moves, grows, uses oxygen and can even spread, but it has no cells: never alive. Crystals grow by adding layers, not by making cells. Robots and cars move and sense things but have no cells, and do not grow or reproduce. Seeds are alive but dormant. Viruses are not cells and can only copy themselves inside a living cell, so they are usually counted as not living.