Answer:
Carbon has the ability to form very strong covalent bonds with its atoms. This property of self-linking with atoms of the same element is termed as catenation.
Catenation is favored by atoms where atom to atom covalent bond is quite strong. In carbon, C-C bond energy is very high (347.3 kJ mol-1) causing catenation. Further, the carbon atom due to its tetravalency, can be bonded to two, three or four carbon atoms by forming single and multiple bonds. Therefore, chains of carbon atoms may be linear, branched or cyclic. Hence, it form long chains of its own atom. Another factor that allows this ability is the very convenient covalent radius of 111 pm.
To date, palytoxin and maitotoxin have been recognized as the longest carbon chain compounds in nature, except for biopolymers such as nucleic acids, proteins, and polysaccharides.