Touch screen
A touch screen is basically a thing that that lets you touch the screen with your finger's. There are touch screen watches,televisions,computers,laptops,phones and etc. You can swipe the screen with your fingers and zoom in. Touch screen was first invented by Steve Jobs in 2007 when he introduced iphone 3g.
what is external and internal?
External hardrive is when you have a seperate hardrive from the computer and Internal hardrive is inside the computer.
Input/output devices
a example of a input device is a keyboard and a output device is a printer
Moniter
The moniter is basically the thing which displays the videos and graphis information generated through the video card
Optical drives
Optical drives are like DVD player but it is actually a blue-ray device which are in your pc and computer e.g it plays high definition video. You can also watch normal cds on it.
Computer Hard Drives
Hardrives are very usefull because the more gaigabytes or tera byes you have, the better it is for your system to be very fast and easy. If your computer or pc is loaded with stuff then your computer or pc is going to be slow and it is going to be better to have a external hard drive. If you dont know what external means then it actually means that it is seperate from your pc or computer. Internal means it is inside the computer.