A full valence shell is the most stable electron configuration. Group 18 elements or noble gases such as helium, neon, and argon, have a full outer, or valence, shell. Elements in other groups have partially-filled valence shells and gain or lose electrons to achieve a stable electron configuration.
They are extremely unreactive and do not form bonds with themselves. Solid helium is the the ultimate fine powder being monotomic.
The Species Survival Plans are supposed to to help ensure the survival of selected species in zoos and aquariums, most of which are threatened or endangered in the wild.
In intravenous ossification, bone develops directly from sheets of mesenchymal connective tissue. In endochondral ossification, bone develops by replacing hyaline cartilage. Activity in the epiphyseal plate enables bones to grow in length. Modeling allows bones to grow in diameter.
Interactions among the amino acid side chains within a single protein molecule determine the protein's tertiary structure. Tertiary structure is the most important of the structural levels in determining, for example, the enzymatic activity of a protein.
There is little to no sunlight in the aphotic zone.
Explanation:
The aphotic zone is the deepest part of a lake/ocean, so no light is able to penetrate into those depths. Without light, photosynthetic organisms will not be able to undergo photosynthesis and will therefore not be able to survive.
