Science / Chemistry / Gas: Matter in a form that has low density, is easily compressible and expandable, and expands spontaneously when placed in a larger container. Molecules in a gas move freely and are relatively far apart. 'Vapor' often refers to a gas made of a substance that is usually encountered as a liquid or solid; for example, gaseous H2O is called 'water vapor'.
Science / Biology / Megaspores: Four haploid cells produced by meiosis in the ovule of a fiower. Usually, three of these cells degenerate, with the remaining cell becoming the female gametophyte phase of the plants life cycle. Large MORE
Business / Machine Shop / Fuel Gas: A gas such as acetylene, natural gas, hydrogen, propane, stabilized methylacetylene propadiene and other fuels normally used with oxygen in one of the oxyfuel processes and for heating. MORE