Answer:
The command to create a compressed archive (archive1.tar.gz) is

Explanation:
The explanation for the above command is
The general command to create a compressed archive is
tar -czvf name-of-archive.tar.gz /path/to/directory-or-files
Here, the terms are as follows:
-c : Creates an archive
-z : Compress the archive with gzip.
-v : This is known as verbose. This is an optional command and it displays the progress on terminal command. Without this the progress is not displayed on terminal command.
-f : Allows to specify the file name of the archive.
Here, if we want to archive multiple files, we provide the command the names of multiple files or directories of the files also can be used.
So, the command 
creates a compressed archive - archive1.tar.gz of files test1, test2 and test3.
<span>An attribute in a relation of a database that serves as the primary key of another relation in the same database is called a</span>
Answer:
the smart phone
Explanation:
It is the most widley used and accepted
Answer:
A. Motherboard has failed.
C. Processor has gone bad or is not seated properly.
Explanation:
The computer system is a digital or electronic device, which comprises of an input device, output device, memory and storage device and a processor, all controlled by a software interface known as the operating system.
The hardware and software components are all integrated on a printed board known as a motherboard.
When the motherboard is faulty, the system looses it functionality and the screen stays off but the power supply indicator light stays on. This is also the same for the processor.