A server baseline is a set of metrics that represents the normal performance and behavior of a server under a specific workload and configuration. A server baseline can help answer the server performance question by comparing the current performance with the previous performance before the upgrade. This can help identify any changes or issues that may have affected the server performance. References:
https://www.comptia.org/training/resources/exam-objectives/comptia-server-sk0-005-exam-objectives (Objective 4.2)

SSH port 22 for secure remote access and 443 is https for encrypted website browsing.

A differential backup is a type of backup that copies all the files that have changed since the last full backup. A differential backup requires more storage space than an incremental backup, which only copies the files that have changed since the last backup of any type, but it also requires less time to restore in case of data loss. By combining a full, weekly backup with daily differential backups, the administrator can ensure that only two backup sets are needed to restore a full backup as quickly as possible. Verified Reference: [Incremental vs Differential Backup]

Explanation
The concept in use when dual power supplies are connected to different power sources is fault tolerance. Fault tolerance is the ability of a system to continue operating without interruption or loss of data in the event of a failure of one or more components. By connecting dual power supplies to different power sources, the system can switch to the alternative power supply or source if one fails, ensuring continuous availability and reliability.
References: CompTIA Server+ SK0-005 Certification Study Guide, Chapter 1, Lesson 1.3, Objective 1.3