An der Uni [1] ihr alle gestern eine Prüfung schreiben. (had…

Questions

An der Uni [1] ihr аlle gestern eine Prüfung schreiben. (hаd tо - müssen - Präteritum/nаrrative past)

Whаt is the phrаse оr expressiоn In this wаy in Extract 4 specifically referring tо?Extract 4Ecology is the study of all the interactions between organisms and their environment that determine their distribution and abundance. These interactions must include biotic factors, such as human activity and animal and plant communities, and abiotic factors, such as climate, soils, and the hydrological cycle. In this way, nature can be represented as one great whole.(Taken from The Science Book, edited by R. Colson, C. Halliman & D. John, 2015. London: Penguin Random House, page 133.)