¿qué van a hacer? these sentences describe what several students in a college hiking club are doing today. use ir a + [infinitiv
e] to say that they are also going to do the same activities tomorrow. follow the model. november 05 11:59 pm 4 attempts remaining grade settings 118-120 grammar presentation modelo martín y rodolfo nadan en la piscina. van a nadar en la piscina mañana también.
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.