Search results
Results from the WOW.Com Content Network
In a large sample of adults of all ages and both sexes, the figure for water fraction by weight was found to be 48 ±6% for females and 58 ±8% water for males. [8] Water is ~11% hydrogen by mass but ~67% hydrogen by atomic percent , and these numbers along with the complementary % numbers for oxygen in water, are the largest contributors to ...
A large fraction of the chemical elements that occur naturally on the Earth's surface are essential to the structure and metabolism of living things. Four of these elements (hydrogen, carbon, nitrogen, and oxygen) are essential to every living thing and collectively make up 99% of the mass of protoplasm. [1]
Atoms can attach to one or more other atoms by chemical bonds to form chemical compounds such as molecules or crystals. The ability of atoms to attach and detach from each other is responsible for most of the physical changes observed in nature. Chemistry is the science that studies these changes.
The nature–culture divide is the notion of a dichotomy between humans and the environment. [1] It is a theoretical foundation of contemporary anthropology that considers whether nature and culture function separately from one another, or if they are in a continuous biotic relationship with each other.
The most important characteristics of carbon as a basis for the chemistry of cellular life are that each carbon atom is capable of forming up to four valence bonds with other atoms simultaneously, and that the energy required to make or break a bond with a carbon atom is at an appropriate level for building large and complex molecules which may ...
Because atoms and molecules are said to be matter, it is natural to phrase the definition as: "ordinary matter is anything that is made of the same things that atoms and molecules are made of". (However, notice that one also can make from these building blocks matter that is not atoms or molecules.) Then, because electrons are leptons, and ...
Get AOL Mail for FREE! Manage your email like never before with travel, photo & document views. Personalize your inbox with themes & tabs. You've Got Mail!
Synthetic biology – research integrating biology and engineering; construction of biological functions not found in nature. Botany – study of plants. Economic botany – study of relationship between people and plants, including the practical uses of plants; Ethnobotany – study of a region's plants and their usage by people