You can use Android Studio (or Eclipse) but you need to learn Java (or C or C++). But Java, C, C++, etc. are very hard to learn so you can use Android App Inventor (ai2.appinventor.mit.edu/ ) which is easier than Android Studio. (Just to know- Android Studio has more capabilities) Prajwal
purchase it from the form of SOF given by your school or go to WWW.MTG.IN (there you get a lot of extra study materials!)
You have to buy the book, there is an Equiz on SOF site and you can download previous year papers from sof olypiad trainer.com
Aditya friend ms word is a website or a app in computer. it means that microsoft word full form. in that we can write things like a letter, applications and more useful writing . and also you go to microsoft word to use. friend best of luck...
McAfee, Norton, Avast, AVG, MalwareBytes, Quick Heal are all antivirus software. Windows Defender is an anti-virus software that comes in-built in Windows
Parasa,your answer does not contain all the anti-virus soft wares . You missed out Kaspersky , it is the best I guess...