Составь характерные для водоёма цепи питания:
а) из трёх звеньев
б) из четырёх звеньев

In a minute you will have to speak about teenage groups and movements. Do not forget to say why teenagers join different groups and movements. what subcultures are popular with teenagers nowadays, why. Why adults are against teenage subcultures. whether you would like to join any subculture, why/why not.