2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/54647Tensionless null p-branes in arbitrary cosmological backgrounds are considered and their motion equations are solved. It is shown that an ideal fluid of null p-branes may be considered as a source of gravity for D-dimensional Friedmann- Robertson-Walker universes.8 pages, LATEX. Submitted to Class.Quantum GravHigh Energy Physics - Theorytext