Paul commutes to and from work each day. although he drives by himself he often speeds along in the carpool lane on the highway. when confronted with his behavior he argues "well, half the drivers in that lane are alone too." paul's response demonstrates

It demontrates that he is a little bit selfish since if travelers are alone it means that there is a waste of gas or that the use of gas is not so efficient and also it is a harm to the environment since to produce gas we cause some damage to the environment.

the answer to your question is,

old stone age.

-mabel < 3