Avastars is generative vector art where the 12 genes that make up an Avastar (Hair Type, Mouth, Skin Tone etc.) have traits (Top Hat, Vampire, Zombie, etc.) randomly assigned to them via browser-based RNG. There are around 450 physical traits and 158 color palette traits that make up the genetic pool of Gen1. As users scroll, Avastars, which are made of these traits show up on their screen. If they find a trait combination they like, they can buy it, which will make it into an NFT.
Decentralized applications (dApps) are digital applications or programs that reside and execute on a blockchain or peer-to-peer network of computers rather than a single computer and are independent of any single authority's control. At Cryptoknowmics, you will get all the information you need to know about Dapps and their use cases.