Proof-of-Work (PoW) is known for its high energy consumption due to the computational effort required to solve complex mathematical puzzles to validate transactions.

In Proof-of-Stake (PoS), the probability of a node being selected to validate a block is primarily determined by the size of its stake, or the amount of cryptocurrency it holds.

Proof-of-Work (PoW) blockchains often face scalability limitations such as high transaction fees, slow transaction confirmation times, and centralization of mining power due to the computational intensity of the mining process.

Sharding in blockchain networks aims to improve transaction throughput by dividing the network into smaller, more manageable partitions called shards, allowing for parallel processing of transactions.

Proof-of-Stake (PoS) is generally considered more energy-efficient compared to Proof-of-Work (PoW) as it does not require intensive computational power to validate transactions.

The main challenge associated with implementing sharding in blockchain networks is managing the inter-shard communication overhead, as transactions may need to be communicated between different shards to ensure data consistency.

Increasing the block size is a straightforward scalability solution that involves allowing blocks to hold more transactions, thereby increasing the network's transaction throughput.

Off-chain transactions are processed outside the main blockchain network, allowing for faster transaction confirmation times and reduced transaction fees, while still maintaining the security and immutability of the blockchain.

The Lightning Network is a scalability solution that involves creating a second layer network on top of the main blockchain, enabling fast and low-cost micropayments through the use of payment channels.

Proof-of-Authority (PoA) consensus mechanism offers high transaction throughput by relying on a predefined set of trusted validators to validate transactions, reducing the computational overhead associated with other consensus mechanisms.

Proof-of-Stake (PoS) blockchains may face scalability limitations due to the centralization of staking power, where a small number of large stakeholders may have a disproportionate influence on the network's decision-making process.

The primary goal of the Lightning Network in blockchain networks is to reduce transaction fees by enabling fast and low-cost micropayments through the use of payment channels, without compromising the security and immutability of the underlying blockchain.

Sharding is a scalability solution that involves dividing the blockchain network into smaller, more manageable partitions called shards, allowing for parallel processing of transactions and improving transaction throughput.

Increasing the block size as a scalability solution may lead to increased latency, as larger blocks take longer to propagate across the network, potentially affecting the speed of transaction confirmation.

Proof-of-Authority (PoA) consensus mechanism relies on a predefined set of trusted validators to validate transactions, reducing the computational overhead associated with other consensus mechanisms and offering high transaction throughput.