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can the ssd hd be replace with 1tb hdd in MacBook Air 11 Early 2015

Yes you can replace your SSD with a 1tb model. However make sure you purchase one that is designed to work with that model as apple designed a proprietary connector for that model. I would recommend purchasing a SSD made by OWC, you can purchase it on iFixit here for the same price the manufacturer sells it for. Here is a step by step tutorial to replace the SSD.