Profesa mmoja wa kemia alisema kwamba baadhi ya vitu vinavyohitajika ili kutokeza uhai ni (1) utando wa kulinda chembe, (2) uwezo wa kupata na kutumia nishati, (3) habari ndani ya chembe za urithi, na (4) uwezo wa kutokeza nakala zaidi za habari hiyo.
The manager of the infrastructure shall charge a fee for the use of the railway infrastructure for which he is responsible, payable by railway undertakings and international groupings using that infrastructurejw2019 jw2019