DNS (Domain Name System) resolves domain names (like example.com) to IP (Internet Protocol) addresses (like 192.168.1.1) that computers use to communicate on a network. This translation is crucial for users to access websites and services using memorable domain names instead of numeric IP addresses.

The worst-case time complexity of heapsort is O(n log n). Heapsort involves two main operations: building a heap (heapify) and repeatedly removing the maximum (for a max heap) or minimum (for a min heap) element. Both of these operations have a time complexity of O(n log n) in the worst case, resulting in heapsort also having a worst-case time complexity of O(n log n). This makes heapsort an efficient sorting algorithm for large datasets.

The heapify algorithm is used to build a heap data structure, particularly in algorithms like heapsort. Heapify involves arranging elements in a way that satisfies the heap property, which can be either a max heap (where each parent node is greater than or equal to its children) or a min heap (where each parent node is less than or equal to its children). This process is fundamental in maintaining the structure and efficiency of operations on heaps.

The correct option is Atomicity. Atomicity in ACID properties ensures that transactions are either committed entirely or rolled back entirely, without any partial execution. This means that if a transaction encounters any error or failure during its execution, all changes made by the transaction are undone to maintain data consistency and integrity. Atomicity is crucial in database management to ensure that transactions are completed successfully or not at all, preventing incomplete or partially executed transactions from affecting the database's overall state.

The logistics route optimization problem can be effectively modeled using a weighted graph, where nodes represent locations (such as warehouses, delivery points) and edges represent routes between these locations. The weights on edges can represent factors like distance, time, or cost between locations. To find the most efficient routes, algorithms like Dijkstra's algorithm or A* algorithm can be applied on the weighted graph. These algorithms consider the weights on edges to find the shortest or most optimized path between two locations, taking into account factors like traffic conditions or delivery priorities. Unweighted graphs, hash tables, or linked lists are not suitable for modeling and solving route optimization problems where factors like distance or cost play a significant role.

Inheritance in Object-Oriented Programming (OOP) allows a class to extend properties and behaviors of another class. When a class inherits from another class, it gains access to its attributes and methods, allowing for code reuse and the creation of hierarchical relationships. This helps in building more complex and structured programs by organizing classes based on their common characteristics and functionalities.

The X-XSS-Protection header is used to mitigate Cross-Site Scripting (XSS) attacks in web applications. XSS attacks involve injecting malicious scripts into web pages, which can then execute in users' browsers, leading to data theft, session hijacking, and other security compromises. The X-XSS-Protection header instructs browsers to activate their built-in XSS protection mechanisms, such as filtering or blocking potentially dangerous scripts, thereby reducing the risk of successful XSS attacks. Implementing this header is an important security measure to safeguard against XSS vulnerabilities and protect users' sensitive information.

The correct option is Presentation. The Presentation layer of the OSI Model deals with the presentation and encryption of data. It is responsible for data translation, encryption, and decryption to ensure that data sent from one system can be properly understood by another system. This layer also handles data compression and decompression. The Data Link layer manages error detection and correction, the Application layer deals with user applications, and the Transport layer ensures end-to-end communication.

The purpose of a sprint retrospective in Agile is to identify areas for improvement within the team's processes, communication, and collaboration. It allows team members to reflect on what went well, what could be improved, and how to implement those improvements in the next sprint. This continuous feedback loop fosters a culture of learning and adaptation in Agile projects.

Cross-site scripting (XSS) is a type of security vulnerability where attackers inject malicious scripts into web pages viewed by other users. These scripts can execute unauthorized actions on the user's behalf, such as stealing session cookies or performing actions on the user's behalf without their consent. This type of attack targets client-side scripts in web applications, making it crucial for developers to validate and sanitize input to prevent XSS attacks.