Botany strengthen the secondary cell walls of xylem tracheids and vessels to keep them from collapsing when a plant sucks water through them under water stress. Lignin is also used in other cell types like sclerenchyma fibres that provide structural support for a plant and is a major constituent of wood. Sporopollenin is a chemically resistant polymer found in the outer cell walls of spores and pollen of land plants responsible for the survival of early land plant spores and the pollen of seed plants in the fossil record. It is widely regarded as a marker for the start of land
Development of Spore pack has been revealed so far, called "galactic adventures" . It will include an adventure editor, as well as many new items and the ability for a player to go down to a planet's surface. On June 24, 2008, the "Spore: Galactic Edition" was announced. This special edition game is priced at $79.99, and includes a "Making of Spore" DVD video, a "How to Build a Better Being" DVD video, by National Geographic Channel (not included in all countries), a "The Art of Spore" hardback mini-book, a fold-out "Spore" poster and a 100-page Galactic Handbook. "Spore" extensively uses procedural generation,