A spanning tree is a subset of the edges of a graph that connects all vertices without any cycles. A minimum spanning tree is specifically the smallest such spanning tree, where the sum of the weights of its edges is minimized. Dijkstra's and Kruskal's algorithms are not specific to defining such subsets in a graph.

Static analysis tools analyze code without executing it, focusing on identifying potential issues, bugs, or violations of coding standards based on code structure, syntax, and patterns. These tools can flag issues such as unused variables, potential memory leaks, or violations of coding conventions like indentation, naming conventions, or code complexity thresholds. They are valuable in ensuring code quality, improving maintainability, and reducing the risk of introducing bugs or vulnerabilities during development. Profiling tools, on the other hand, focus on runtime behavior and performance metrics, coverage tools assess test coverage, and code review involves manual or automated inspection of code by peers or tools.

Dynamic testing involves executing the software to find defects or bugs. It includes techniques like unit testing, integration testing, system testing, and acceptance testing, where the software is actively run to check its behavior and functionality. This type of testing is essential for identifying issues that may arise during actual usage of the software.

Using WebSocket allows real-time communication between clients and the server, making it ideal for notifying users when someone is typing. setTimeout and clearTimeout are more suitable for handling delays and timeouts, not real-time updates. AJAX polling introduces unnecessary overhead and delays. The oninput event listener is used for detecting input changes, not real-time status updates.

Merge sort is a classic example of a divide and conquer algorithm, where the sorting process involves dividing the array into smaller subarrays, sorting them individually, and then merging them back together in sorted order.

Singly linked lists only allow traversal in one direction, from head to tail, while doubly linked lists allow traversal in both directions, which enhances flexibility but comes with higher memory overhead.

The correct option is Content-Type. The Content-Type header in HTTP requests and responses specifies the media type of the data being sent or received. For example, it can indicate whether the data is in JSON, XML, HTML, or another format. This header helps the client and server understand how to handle the data appropriately.

In a legacy system, normalization involves identifying redundant data and dividing tables to eliminate anomalies such as update, insertion, and deletion anomalies. This is achieved by breaking down data into fewer tables, using foreign keys to establish relationships, and ensuring data integrity. Combining tables or using non-normalized data would not address the underlying issues of redundancy and anomalies.

The block size in a file system plays a crucial role in determining the speed of file access. A smaller block size can lead to more efficient storage utilization for small files but may result in increased overhead for large files due to more blocks being allocated. On the other hand, a larger block size can improve the performance of accessing large files but may lead to wasted space for small files. Therefore, the block size choice depends on the expected file sizes and access patterns in a given system, balancing efficiency and performance accordingly.

The ACID property that ensures transactions are isolated from each other to prevent interference is Isolation. Isolation ensures that concurrent transactions do not see each other's intermediate states, thus preventing interference and maintaining data integrity.