DeFi is taking on the contractual agreement you find on the global financial system in a permisonless and open way. MakerDao was the first DeFi project started in 2015
a) #Lending & #Borrowing:- These are algorithmic autonomous interest protocols that allow users to supply protocols like ether etc.Eg: Compound and Aave
c) #Dexes(Decentralized Exchanges):- Allow exchange of crypto asset in a completely decentralized & permissionless way without giving up the custody of the coins.types of dexes: liquidity pool dexes: uniswap, sushi,and Booked dexes: Loopring