Feu servir l’exemple d’un bosc o un estany per definir el concepte d’ecosistema tal com el proposa l’autor. Ens aquestes casos, quins serien els elements físics que els caracteritzen? I els biològics? Quin tipus d’interaccions creieu que s’hi estableixen?

Which revelation resulted from the observation of the spectrum of different galaxies? a. there were more galaxies whose spectrum was blueshifted b. there were no galaxies whose spectrum was redshifted c. there were more galaxies whose spectrum was redshifted d. there were no galaxies whose spectrum was blueshifted