A SIM card is needed for the device to use cellular network services, so without it, the device will be unable to connect to the cloud services when taken off site. MDM (Mobile Device Management) can be used to manage settings and access on a device, but it is not necessary for the device to be able to use cloud services. S/MIME (Secure/Multipurpose Internet Mail Extensions) certificates are used to encrypt and digitally sign emails, and are not related to device connectivity. Bluetooth can be used to connect devices together, but it is not necessary for the device to be able to use cloud services.

To increase the volume on a laptop using only a keyboard, a user can press and hold down the Fn key while pressing one of the function keys (usually F1-F12) that has an icon representing volume up.

The correct answers are C. Rollers and E. Heating element.
A 3in (2.5cm) point-of-sale printer is a type of thermal printer that uses heat to print receipts on special thermal paper. The printer has a heating element that heats up the paper as it passes through the rollers, creating black marks on the paper where the heat is applied. The heating element and the rollers are two critical components of the thermal printer that can affect the quality of the printout.
If the printer is only printing fully black receipts, it means that the heating element is overheating or malfunctioning, causing the entire paper to turn black. The heating element may need to be replaced or repaired by a technician. Alternatively, the rollers may be dirty or damaged, causing the paper to stick to the heating element and get burned. The rollers may need to be cleaned or replaced by a technician.
The other options are not likely to cause the printer to print fully black receipts. The power supply may affect the printer's performance, but it would not cause the heating element to overheat or the rollers to malfunction. The humidity and room temperature may affect the quality of the thermal paper, but they would not cause the entire paper to turn black. The fuser is a component of a laser printer, not a thermal printer, and it has no effect on the point-of-sale printer.
Reference:
Basic Printer Troubleshooting - Individual Point of Sale
5 Common Issues With Any POS System and How To Fix Them
Printer Troubleshooting | Square Support Center - US
Resolve receipt printer issues and cash drawer will not open - QuickBooks

http://www.221021.com/Hardware/input-output-devices/32310.html
1. Identify the problem.
Gather information from the user, identify user changes, and, if applicable, perform backups before making changes.
Inquire regarding environmental or infrastructure changes.
2. Establish a theory of probable cause (question the obvious).
If necessary, conduct external or internal research based on symptoms.
3. Test the theory to determine the cause.
Once the theory is confirmed, determine the next steps to resolve the problem.
If the theory is not confirmed, re-establish a new theory or escalate.
4. Establish a plan of action to resolve the problem and implement the solution.
Refer to the vendor's instructions for guidance.
5. Verify full system functionality and, if applicable, implement preventive measures.
6. Document the findings, actions, and outcomes.

The message stating that one or more disks are in a degraded state is a clear indication of a RAID failure. RAID stands for Redundant Array of Independent Disks, and it is a technology used to provide fault tolerance and improve performance by combining multiple hard drives into a single logical unit.
The message indicating that the OS is missing is most likely caused by a bootable device not found. This means that the server is unable to boot from the designated boot device, which could be the hard drive, a CD/DVD drive, or a USB flash drive. This could be caused by a faulty boot device, a loose cable, or a misconfiguration in the BIOS or UEFI settings.