Answer Description
User Account Control (UAC) is a feature in Windows 7, 8 and 10 that prompts users to confirm changes initiated by software. Until the changes are confirmed by UAC the change will not be made. This helps users understand when they are making system level changes like installing a new application. Sudo is a similar feature in Linux operating systems. NTFS is a file system and Windows Defender is an anti-malware application.
Wikipedia
User Account Control (UAC) is a mandatory access control enforcement feature introduced with Microsoft's Windows Vista and Windows Server 2008 operating systems, with a more relaxed version also present in Windows 7, Windows Server 2008 R2, Windows 8, Windows Server 2012 and Windows 10 It aims to improve the security of Microsoft Windows by limiting application software to standard user privileges until an administrator authorizes an increase or elevation In this way, only applications trusted by the user may receive administrative privileges, and malware should be kept from compromising the operating system In other words, a user account may have administrator privileges assigned to it, but applications that the user runs do not inherit those privileges unless they are approved beforehand or the user explicitly authorizes it
User_Account_Control - Wikipedia, the free encyclopedia