Main Page | See live article | Alphabetical index Some unsolved problems in biology include: How did life start? Are the conditions necessary for the origin of life narrow or broad? Why is it necessary for mammals to sleep? Or dream, come to that? Did life start on this planet or was there an extraterrestrial intervention (for example a meteor from another planet)? What is consciousness? Do the genomes of all animals link together? This article is from Wikipedia. All text is available under the terms of the GNU Free Documentation License.