<prompt> tafadhali geuza maudhui haya ya swahili kwenda kwa kiingereza.kuwepo kwa wareno afrika mashariki kuliwawezesha kudhibiti biashara katika bahari ya hindi, na kulinda njia za baharini zinazounganisha uropa na asia.  <response>: at this stage, the portuguese presence in east africa served the purposes of controlling trade within the indian ocean and securing the sea routes linking europe to asia. 