Smart Contracts are self-executing programs that automate transactions and eliminate the need for

intermediaries. They operate on blockchain networks and are coded to execute specific actions when

predetermined conditions are met.

Key Details:

Transaction Automation: Smart contracts automatically execute the terms of a contract once the

agreed-upon conditions are fulfilled. This reduces manual processing and ensures transparency and

trust between parties.

Elimination of Intermediaries: By running on a decentralized network, smart contracts eliminate the

need for third-party intermediaries, such as lawyers or notaries, reducing transaction costs and

increasing efficiency.

Application Across Industries: Smart contracts are used in various sectors, from finance and supply

chain to insurance and real estate, due to their ability to enforce terms without human intervention.

Therefore, D. Smart contracts is the correct answer, as they facilitate automated transactions and

remove the need for intermediaries.

Blockchain technology has significant potential in the energy industry, particularly in energy trading

and smart power grids. By providing a transparent, decentralized, and secure platform for

transactions, blockchain can facilitate peer-to-peer energy trading and improve the efficiency and

reliability of smart grids.

Key Details:

Energy Trading: Blockchain enables peer-to-peer energy trading where individuals and companies

can buy and sell excess energy (such as solar or wind power) directly to each other. This

decentralized model reduces the need for intermediaries and allows consumers to benefit from

direct energy sales and purchases.

Smart Power Grids: Blockchain can enhance smart grid systems by enabling real-time data sharing

and automated decision-making. With blockchain, smart grids can securely record and share data

related to energy production, consumption, and storage, thereby improving grid management,

reducing waste, and optimizing energy distribution.

Enhanced Transparency and Security: By recording all transactions in an immutable ledger,

blockchain ensures transparency and security, reducing the risks of fraud and discrepancies in the

energy market. This is especially beneficial in energy trading where trust and accurate record-

keeping are essential.

Thus, Energy trading (B) and Smart power grids (D) are the most likely use cases for blockchain in the

energy industry.

A Fully Anonymous DApp is a decentralized application that is designed to maintain complete

anonymity for all participants. These DApps do not require user identity verification, and interactions

are carried out in a manner that does not reveal personal information. Fully anonymous DApps are

particularly popular in privacy-focused blockchain ecosystems.

Key Details:

Privacy and Anonymity: Fully anonymous DApps employ various privacy-preserving techniques, such

as zero-knowledge proofs or ring signatures, to ensure that user transactions and interactions cannot

be traced back to their identities.

Use Cases: Fully anonymous DApps are often used in applications where privacy is paramount, such

as private transactions, anonymous messaging, and confidential voting systems. By design, they

prioritize user anonymity over other features.

Comparison with Other DApp Types: While other DApp types might include some level of user

identification or reputation systems, fully anonymous DApps offer total anonymity, making them

ideal for users who require privacy at all levels of interaction.

Therefore, A. Fully anonymous DApp is the correct answer, as it describes a DApp that allows

participants to remain completely anonymous.

Public blockchains most commonly use Proof of Work (PoW) as their consensus mechanism,

especially in well-established networks such as Bitcoin and, until recently, Ethereum. PoW is a

protocol that relies on network participants (miners) solving complex mathematical problems to

validate and add transactions to the blockchain. This process ensures the integrity and security of the

network, as it requires substantial computational power and resources, making it difficult for any

single entity to control the blockchain.

Key Details:

Proof of Work (PoW): PoW, used primarily by Bitcoin, operates by having participants (often referred

to as miners) compete to solve cryptographic puzzles. The first to solve the puzzle adds the next

block of transactions to the blockchain and is rewarded with newly minted coins. This system is

energy-intensive but is widely recognized for its security and resistance to tampering.

Transition in Other Networks: While Ethereum initially used PoW, it transitioned to Proof of Stake

(PoS) in 2022 with Ethereum 2.0, due to PoS's lower energy requirements and increased scalability.

However, Bitcoin, the most prominent public blockchain, still relies on PoW.

Other Consensus Mechanisms: Alternatives such as Proof of Stake (PoS) and Proof of Burn (PoB) are

used by other blockchain networks that aim for different trade-offs in terms of energy efficiency,

scalability, and security. Proof of Elapsed Time (PoET) is another mechanism mostly associated with

permissioned (private) blockchains rather than public blockchains.

Why PoW for Public Blockchains?: Public blockchains prioritize decentralization and security. PoW

provides a robust way to achieve this, despite its high energy consumption. Its high level of security

and historical success in Bitcoin’s network often make it the go-to choice for public blockchains.

In summary, the dominance of PoW in public blockchains is due to its established security and

proven track record, although PoS and other mechanisms are increasingly gaining popularity for their

efficiency in newer blockchain projects.

Solidity is the primary programming language used for developing smart contracts on the Ethereum

blockchain. It is a statically typed, high-level language similar to JavaScript and C++, and it is

specifically designed for creating contracts that run on the Ethereum Virtual Machine (EVM).

Key Details:

Purpose of Solidity: Solidity was created by the Ethereum team to enable the development of smart

contracts that automate the execution of blockchain-based applications. Its syntax is designed to be

familiar to developers experienced in other programming languages, which helps in onboarding and

learning.

Compatibility and Flexibility: As a Turing-complete language, Solidity allows for the development of

complex smart contracts and decentralized applications (DApps) with conditional logic, loops, and

more. It is widely used in the DeFi space and beyond.

Ethereum Test Networks: Other options listed, such as Rinkeby and Kovan, refer to Ethereum test

networks where developers test smart contracts, but they are not languages themselves. Mist is an

Ethereum wallet interface, not a programming language.

Thus, C. Solidity is the correct answer, as it is the language specifically designed for working with

Ethereum smart contracts.

The primary benefit of blockchain in the healthcare industry for patients is total control over personal

health records. Blockchain enables secure, decentralized storage of health data, allowing patients to

control access to their information and share it with healthcare providers as needed.

Key Details:

Data Ownership and Privacy: Blockchain gives patients the ability to own and manage their health

records. They can grant or revoke access to different healthcare providers, ensuring that only

authorized personnel have access to their data.

Improved Security: Health records stored on a blockchain are encrypted and decentralized, making

them resistant to tampering and unauthorized access. This enhances patient privacy and reduces the

risk of data breaches.

Interoperability and Accessibility: Blockchain facilitates seamless sharing of health records across

different healthcare providers and systems, improving coordination and care continuity without

compromising data integrity.

Therefore, B. Total control over personal health records is the correct answer, as it represents a

significant advantage for patients in managing their healthcare information securely.

The UTXO (Unspent Transaction Output) model establishes a chain of ownership by using digital

signatures. In this model, each transaction consists of inputs (from previous UTXOs) and outputs

(new UTXOs), and ownership is transferred by the current owner signing the transaction. This digital

signature is then verified by the recipient, ensuring a secure and traceable chain of ownership.

Key Details:

Functionality of UTXO: UTXO is a fundamental part of Bitcoin’s transaction model. When a

transaction occurs, it consumes previous outputs as inputs, generating new UTXOs. Each UTXO can

only be spent once, and ownership is verified through cryptographic signatures.

Chain of Ownership: The UTXO model inherently creates a clear and verifiable chain of ownership, as

each output is signed by the current owner and used as input for future transactions, maintaining a

continuous and transparent record of asset transfers.

Security through Digital Signatures: UTXO-based transactions rely on digital signatures to

authenticate and authorize asset transfers, ensuring that only the rightful owner can initiate a

transaction.

Thus, D. UTXO is the correct answer, as it accurately describes the model where ownership is

established through a chain of digital signatures.

A Type II DApp is a decentralized application that uses both the blockchain and protocol of a Type I

DApp. Type I DApps are the foundational blockchain-based platforms, such as Ethereum, that operate

with their own blockchain. Type II DApps build on these platforms, using the existing blockchain and

protocol, but offering specific functionalities or services.

Key Details:

Type I DApps: These are fundamental blockchain platforms, like Bitcoin or Ethereum, which have

their own blockchain and provide a foundation for other applications.

Characteristics of Type II DApps: Type II DApps leverage the infrastructure of Type I DApps but add

additional functionality through smart contracts or protocols. For example, protocols such as ERC-20

tokens or ERC-721 NFTs are built on Ethereum and utilize Ethereum's underlying blockchain and

consensus protocol.

Integration: By utilizing both the blockchain and protocol of a Type I DApp, Type II DApps inherit the

security, decentralization, and features of the underlying Type I platform, which simplifies their

development and ensures compatibility.

In summary, B. Using the blockchain and protocol of a type I accurately describes the categorization

of Type II DApps.

A hard fork occurs when there is a fundamental change in a blockchain’s protocol, resulting in the

creation of a new chain that is incompatible with the previous one. After a hard fork, nodes must

upgrade to the new version of the blockchain’s software to continue participating in the network. A

hard fork can be used to implement new features, fix security issues, or change core aspects of the

blockchain.

Key Details:

Differences from Soft Forks: Unlike a soft fork, which is backward-compatible and allows nodes on

the previous version to still participate, a hard fork splits the blockchain into two distinct paths, with

the upgraded path requiring new software.

Examples: Notable hard forks include Bitcoin Cash from Bitcoin and Ethereum Classic from Ethereum.

These forks occurred due to disagreements within the community on how to handle certain protocol

changes, leading to the creation of separate blockchains.

Upgrade Requirements: Participants on the blockchain who wish to continue on the new chain after

a hard fork must update their software. Those who do not upgrade remain on the original chain,

which continues as a separate, incompatible blockchain.

Thus, the correct answer is Hard fork (A), as it directly refers to a blockchain split that requires client

upgrades for participation.

According to studies conducted by Deloitte and other industry research, blockchain offers several

benefits for the insurance industry, particularly in more efficient claims processing and lower costs.

Blockchain’s capabilities in data immutability, transparency, and automation play key roles in

streamlining insurance processes and reducing operational expenses.

Key Details:

Efficient Claims Processing: Blockchain enables quicker verification and processing of claims by

automating workflows through smart contracts. This reduces paperwork, minimizes errors, and

speeds up the claims process, improving customer satisfaction.

Lower Costs: By reducing intermediaries and leveraging automation, blockchain lowers

administrative costs. It minimizes the need for manual verification and fraud detection, which

traditionally consume significant resources in the insurance industry.

Transparency and Fraud Reduction: Blockchain provides an immutable and transparent record of all

transactions. This helps prevent fraud, as all stakeholders have access to the same data, reducing

discrepancies and the need for extensive audits.

In conclusion,

A. More efficient claims processing and

D. Lower costs are the correct answers, as

these are key benefits of blockchain for the insurance industry identified in Deloitte’s research.