changedQuestion 1 with 2 blanks Esteban y Julio tienen You answered una tía. Es ellos You answered tía. changedQuestion 2 with 2
blanksYo tengo You answered muchos amigos. Son yo You answered amigos. changedQuestion 3 with 2 blanksTú tienes You answered tres primas. Son tú You answered primas. changedQuestion 4 with 2 blanksMaría y tú tienes You answered un hermano. Es tú You answered hermano. changedQuestion 5 with 2 blanks Nosotras tenemos You answered unas mochilas. Son nosotras You answered mochilas. changedQuestion 6 with 2 blanksUsted tiene You answered dos sobrinos. Son usted You answered sobrinos.
Scientists think that algae first evolved approximately 2.7 billion years ago, and soon after this oxygen began to exist in the atmosphere. Photosynthesis by primitive plants and algae released oxygen, which gradually built up in the atmosphere.
