What is the difference between seeds and peers?

The greater number of seeds will contribute to a faster speed of downloading the file, whereas a more significant number of peers will mean that the speed of downloading will be less. Seeds upload the whole files, while peers only upload the parts of the files they have and download the other parts of the file they don’t have.

How does a peer become a seed?

A peer becomes a seed when he has completed 100% of the file and wishes to continue uploading. A user who wants to upload a file first creates a small torrent descriptor file that they distribute by conventional means (web, email, etc.). They then make the file itself available through a BitTorrent node acting as a seed.

Why is a seeder called a peer?

They are named peers, because you are in the same "boat" as them, both in the process of downloading. Seeders are more reliable, because you are able to download the entire file from them. You can only get a certain amount of the file (s) from the peers, but not all. So a file with only 1 peer and no seeds, for example, will never download in full.