To get an operation done in Ethereum, the sender of the transaction must specify a gas limit before they submit it to the network & a gas price: 

• The gas limit is the maximum amount of gas the sender is willing to pay for this transaction. If an operation has LOW gas, ...

If bitcoin is digital gold, Ethereum is alike the power grid, powering an ecosystem of worldwide decentralized applications. 

The gas is the metering system for the consumed power. And ETH is the currency used to pay for running the software and maintaining the network. 

Polygon validators periodically perform checkpoints against the Ethereum main chain, as a mechanism to settle any transaction disputes that occur on the sidechain through cryptographic proof. 

• Users can transfer tokens across Matic without incurring third-party risks a...