What is difference between a backdoor, a bot, a keylogger, and psyware, a nd a rootkit? Can they all present in the same malware?

Yes, they can all be present in the same malware because each of them perform slightly differing functions.

Explanation:

Backdoor is a software which when placed into your computer will permit hackers to easily gain reentry into your computer. This can happen even after you have already patched the flaw that they have used to hack your system before.

A bot is a program that does the same task in a continuous manner akin to when you use a blender by pressing the button to blend what you have put into it.

A keylogger is a part of a hidden software that monitors and records everything you type on your computer keyboard after which it writes it onto a file, with the hopes of capturing relevant information such as your bank account number and even passwords and other sensitive means of identification.

A Spyware is somehow similar to a keylogger just that it steals information from your computer and sends it to someone else.

A root kit is a bad software that is capable of modifying the operating system or other privileged access devices in order to gain continuous access into your system for the purpose of gathering of information and/or reducing the system’s functionality.

Yes, they can all be present in the same malware because each of them perform slightly differing functions.

b. check your rearview mirror

explanation:

the warning light flashes for a second or two when the engine starts. if it stays on, there's must be something wrong with the coolant. you should never dare to continue driving when the light is on. pull over as soon as possible and shut the engine off.

hope this is what you're talking about