Living organisms are composed of millions of organic compounds each have a unique structure which element is responsible for this huge diversity of molecules describe the diversity of structures that can be formed and the properties of the element that allow diversity of form to occur

Carbon is the element that is responsible for the huge diversity of organic molecules, which are the compounds in the living organisms.

The diversity of organic molecules' structures is really huge and it includes alkanes, alkenes, alkines, linear molecules, cyclic molecules, and molecules with special functional groups.

Alkanes are molecules with only single bonds between any carbons.

Alkenes have one ore more double bonds between some carbons.

Alkines have one or more triple bonds bwtween some carbons.

Cyclic molecules form close rig structures.

Molecules with functional groups include: carbon halides, alcohols, eters, amines, aldehides, ketones, carboxilic acids, esters and amides.

The huge diversity of compounds that can be made up with carbon is due to its ability to form four bonds, which permit to form chains.

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Anay of those bonds cand be joined to many different elements, H, halogens, oxygen, nitrogen, phosphorus, sulfur, and other C, which in turn can bond to the same range of elements, and so form an infinite range of compounds.

The answer is d., a mountain.