# data[].attributes.body
Carbon is key to life and by definition is present in all organic compounds. The study of life is known as biological chemistry or biochemistry. Ethene gas (C₂H₄) helps to ripen tomatoes.

# data[].attributes.body
Calcium is essential for all life. It forms part of cell walls and bones. It is important for blood clotting.

# data[].attributes.body
Bromine may be an essential trace element for red algae and possibly mammals. It is found in the mollusc pigment "royal purple", although its role is not understood. Excessive bromide intake leads to depression and of weight loss.

# data[].attributes.body
Aluminium metal is not found as the free element, however, aluminium is an abundant element in the earth's crust. The most important ore is bauxite.

# data[].attributes.body
Nitrogen is a key component of biological molecules such as proteins (which are made from amino acids, and nucleic acids. The nitrogen cycle in nature is very important.

# data[].attributes.body
Nickel is an essential trace element for many species. Chicks and rats raised on nickel-deficient diets have liver problems. Enzymes known as hydrogenases in bacteria contain nickel. Nickel is also important in plant ureases.

# data[].attributes.body
Neon gas is present in the atmosphere at about 1 part in 65 000.

# data[].attributes.body
Magnesium is an important element for plants and animals

# data[].attributes.body
Lithium is mixed (alloyed) with aluminium and magnesium for lightweight alloys, and is also used in batteries, some greases, some glasses, and in medicine.

# data[].attributes.body
Lead has no biological role. Lead affects the gut, central nervous system and causes anaemia.

# data[].attributes.body
Mercury only occurs rarely as the free element in nature. Overall, it is a rare element in the earth's crust. Its main source is cinnabar ore (HgS) from Spain and Italy. The Alma den mine in Spain has been in continuous operation since 400 BC. Other sources include Yugoslavia, Russia, and North America.

# data[].attributes.body
Iron compounds are essential to all life. For example, it is an iron atom in hemoglobin that is responsible for carrying oxygen around the blood stream.

# data[].attributes.body
Iodine is an essential component of the human diet and in fact appears to be the heaviest required element in the diet. Iodine compounds are useful in medicine.

# data[].attributes.body
Hydrogen is the lightest element. It is by far the most abundant element in the universe and makes up about about 90% of the universe by weight. It is also the most abundant element in the earth's sun.

# data[].attributes.body
Zinc-deficient animals require 50% more food to gain the same weight of an animal supplied with adequate amounts of zinc. Zinc is not particularly toxic and is an essential element in the growth of all animals and plants.

# data[].attributes.body
Uranium is surprisingly common and is more plentiful than mercury, silver, or cadmium in the earth's crust, and is about as abundant as molybdenum or arsenic.

# data[].attributes.body
Tin resists distilled, sea, and soft tap water, but is attacked by strong acids, alkalis, and acid salts. Oxygen in solution accelerates the attack. When heated in air, tin forms SnO₂. It is, or was, used to plate steel, making "tin cans". Tin is used as one component in bell metals.

# data[].attributes.body
Sulphur is found in meteorites, volcanoes, hot springs, and as galena, gypsum, Epsom salts, and barite. It is recovered commercially from "salt domes" along the Gulf Coast of the USA.

# data[].attributes.body
Oxygen gas (dioxygen, O₂) makes up 21% of the atmosphere by volume. It is the most abundant element in the earth's crust (followed by silicon).

# data[].attributes.body
The human diet must contain a sensible amount of sodium.

# data[].attributes.body
Phosphorus is a key component of biological molecules such as DNA and RNA. Phosphorus is a component of bones, and teeth, and many other compounds required for life.

# data[].attributes.body
Pure silver has the highest electrical and thermal conductivity of all metals, and possesses the lowest contact resistance.

# data[].attributes.body
Silicon makes up 25.7% of the earth's crust by weight, and is the second most abundant element, exceeded only by oxygen.

# data[].attributes.body
Potassium is a metal and is the seventh most abundant and makes up about 1.5 % by weight of the earth's crust.