In high-traffic e-commerce websites, in-memory caching with tools like Redis is crucial. It helps store frequently accessed data in memory, reducing the need to query the database repeatedly, and thus improving performance during peak times.

When resolving conflicts in Git, the modified files must be staged (using "git add") after resolving the conflict but before committing the changes. Staging indicates that the conflicts have been addressed and are ready to be included in the next commit.

Git marks merge conflicts in the affected files using special conflict markers like <<<<<<<, =======, and >>>>>>>. These markers indicate the conflicting sections that need manual resolution.

Cache coherency in distributed systems ensures that all nodes have consistent data by synchronizing their caches. It prevents data inconsistencies across the network.

In Git, a "conflict" occurs when the changes in two branches are Incompatible. This happens when Git can't automatically merge changes due to conflicting modifications in the same lines of code. Resolving conflicts is necessary before completing the merge or rebase.

A deadlock occurs when two or more transactions are waiting indefinitely for each other to release locks, leading to a situation where none of the transactions can proceed. Deadlocks must be resolved to allow the system to continue processing transactions.

Ensuring the security of sensitive customer data involves multiple measures. HTTPS with SSL/TLS secures data in transit, regular software updates patch vulnerabilities, and storing sensitive data encrypted protects it even if there's unauthorized access.

The tag defines an image in an HTML document. It is a self-closing tag that requires attributes like src (source) to specify the image file path.

In a distributed microservices architecture, using centralized logging and monitoring tools is crucial for effective troubleshooting and performance optimization. This approach provides a unified view of the entire system, aiding in identifying issues and optimizing performance. Individual service logs may not offer a holistic perspective. Alert-based monitoring alone might miss subtler issues, and logging everything at maximum verbosity can lead to excessive data and performance overhead.

Using descriptive commit messages and proper documentation can help in understanding and resolving merge conflicts more effectively. Clear communication through commit messages aids in tracking changes and makes it easier to comprehend the context of conflicting modifications.

To fix a critical bug in production using Gitflow, create a hotfix branch, make the necessary changes, merge it into both master (for the release) and develop (to ensure the fix is in future releases), and then tag the release for tracking purposes.

Resolving a merge conflict in Git requires reconciling the conflicting changes made in different branches. Developers need to edit the files to harmonize the modifications and create a unified version.