2D & 3D Animation
Details
2D ANIMATION :
The creation of moving pictures in a two-dimensional environment, such as through
"traditional" cel animation or in computerized animation software.
This is done by sequencing consecutive images, or "frames", that simulate motion by
each image showing the next in a gradual progression of steps.
3D ANIMATION:
The creation of moving pictures in a three-dimensional digital environment.
This is done by sequencing consecutive images, or "frames", that simulate motion
by each image showing the next in a gradual progression of steps, filmed by a virtual "camera"
and then output to video by a rendering engine.
To create the illusion of life
A simulation  of movement created by displaying a series of pictures, 
or frames. Cartoons on television is one of several examples of animation..
Animation on computers is one of the chief ingredients of multimedia presentations.
There are many software applications that enable you to create animations that you
can display on a computer monitor. There is a notable difference between animation and video.
Whereas video takes continuous motion and breaks it up into discrete frames, animation
starts with independent pictures and puts them together to form the illusion of continuous motion.