Rootkits and botnets:

A rootkit is set ot some utilities which helps to take acess of root or kernel, it works in backgroud with injection core level to control system . Also hidden on your computer without your knowledge. It may be included in a larger software package or installed by an attacker who has been able to take advantage of a vulnerability on your computer or has convinced you to download it. Rootkits are not necessarily malicious, And not part of malware but they may hide malicious activities or protect. Attackers is able to access information, monitor your actions, modify programs, or perform other functions on your computer without being detected.
Botnet ia part of bots, but which works with mal code, & its designed as automated program or robot. Generally attacker access control by injecting into computers with a malicious code that allow the attacker access. It works in hidden mode noone can detect or get know its present in system. Botnets are mostly used to calculate a range of activities, from spam and viruses to denial-of-service attacks.

Speculate as threats:

Rootkits & botnets both works in system backend proccess with gain of multipal core system component, but with the same way botnets are not hidden as rootkits are, they undetected if you are specifically looking for some special activity. If a rootkit has been installed, you may not be know that your computer is under attack and Security software not able to detect the malicious programs. Attackers use rootkits and botnets to gain access and change personal information, attack on other computers, and commit other crimes, all meanwhile undetected. By using uncountable computers,

Steps Towards protection:

If you are aware about good security techniques,then you can reduce the risk that your system will be compromised:

Security software - Anti-virus software known and protects your system against most recongnized viruses or malicious programs, so you could able to detect and clean the infection before it can do any damage. Because vaients are always getting modify, It is most important to keep your antivirus up to date with latest virus signatures. Some of anti-viruses also offer anti-rootkit.
Install a firewall - Firewalls are able to block and prevent some types of attakcs by blocking malicious traffic before it can enter your system. Some operating systems include a firewall, but just make sure its enabled with proper rule configurations.
Use Random passwords – Always keep changing password with random charachters like *, words, and Do not save your password in your browser in any case.
Update security patches- Install Vurnalablity patches so that attackers can't get known problems or bugs in system. Geunine operating systems offers automatic updates, you should enable it.
Always try to be Updated- Always be aware and take precautions when using email and web browsers that your actions will invite an infection.
Unfortunately, if there is a rootkit in your system or an attacker is using your system with a botnet, you cant find it. Even if you get know that you are a victim, its difficult for the users to troublshoot with it, in those case forward case to a trained system administrator.
And with diffrent way, Developers are creating products and tools that can 0remove a rootkit from your system.

Thanks & Regards
Sagar shelar