Abstract: I will present ongoing work dealing with characterising the nature of star formation in galaxies through cosmic time, particularly from the point of view of the fueling of their activity and the measurement of their gas reservoirs, emphasizing current limitations in the understanding. I will focus of the main classes of distant galaxies: main sequence and starburst but also quiescent, and discuss interesting recent developments on the role of environment in driving galaxy buildup, mostly based on a number of ongoing ALMA projects.