Which of the following statements best describes why carbon can form a variety of organic compounds? carbon atoms bond readily with oxygen atoms. carbon readily forms covalent bonds with other carbon atoms. carbon atoms have very high electronegativity values. carbon readily forms ionic bonds with other carbon atoms.

            Carbon readily forms covalent bonds with other carbon atoms.

Explanation:
                   As we know approximately more than 95 % compounds, either isolated, discovered or synthesized belongs to organic compounds containing carbon atoms.
                  This great diversity of organic compounds is due to following facts.

1) Catenation:
                      Carbon has a peculiar behavior of self linkage. This self linkage of one carbon with another is called as catenation. In this way carbon can form a long chain of carbon atom. A branching can also take place when one carbon is bonded further to three of four carbon atoms.

2) Isomerism:
                     Secondly the carbon containing compounds show isomerism. In which molecular formula is same but structural formula is different. For example molecular formula C₅H₁₂ can make following compounds,

                                a)  n-Pentane

                                b)  2-Methylbutane

                                c)  2,2-Dimethylpropane

3) Multiple Bonds:
                            Carbon can form multiple bonds i.e double bond like in alkenes and triple bonds like in alkyne. 

Due to these factors carbon gets very high number of opportunities to form large number of compounds.