Copper is a chemical element with the symbol Cu (from cuprum) and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; a freshly exposed surface has a reddish-orange color. It is used as a conductor of heat and electricity, a building material, and a constituent of various metal .
A social network is a social structure made up of a set of social actors (such as individuals or organizations), sets of dyadic ties, and other Social relation between actors. The social network perspective provides a set of methods for analyzing the structure of whole social entities as well as a variety of theories explaining the patterns observed in these structures. ξ1 The study of these structures uses social network analysis to identify local and global patterns, locate influential entities, and ..
The Mars Society is a space-advocacy non-profit organization dedicated to promoting the human exploration and settlement of the planet Mars. Inspired by "The Case for Mars" conferences which were hosted by The Mars Underground at the University of Colorado Boulder and established by Dr. Robert Zubrin and many others in 1998, the organization works to educate the public, the media and government on the benefits of Mars exploration and the importance of planning for a Earth-to-Mars mission in the coming dec..
Zinc, in commerce also spelter, is a chemical element; it has the symbol Zn and atomic number 30. It is the first element of group 12 of the periodic table. Zinc is, in some respects, chemically similar to magnesium, because its ion is of similar size and its only common oxidation state is 2. Zinc is the 24th most abundant element in the Earth's crust and has five stable . The most common zinc ore is sphalerite (zinc blende), a zinc sulfide mineral. The largest mineable amounts are found in Australia, A..
A zygote (from Greek ζυγωτός zygōtos "joined" or "yoked", from ζυγοῦν zygoun "to join" or "to yoke"), is the initial cell formed when two gamete cells are joined by means of sexual reproduction. In multicellular organisms, it is the earliest developmental stage of the embryo. In single-celled organisms, the zygote divides to produce offspring, usually through Mitosis, the process of cell division.
A flagellate is an organism with one or more whip-like organelles called flagella. Some cells in may be flagellate, for instance the spermatozoa of most phyla. do not produce flagellate cells, but , , green algae, some gymnosperms and other closely related plants do. Likewise, most fungi do not produce cells with flagellae, but the primitive fungal do. Many take the form of single-celled flagellates.
