Search engines are programs that search for and identify items based on a user input keyword, phrase, etc. Examples include google, bing, etc.
Creating a list of keywords and using them throughout your
site helps move pages up the ranks of search engines like Bing or Google. They
also attract website visitors. Technically, maintaining a list of keywords
while creating a webpage is important in search engine optimization.
The answer is projectile. Handguns and rifles use a cartridge having a single projectile or bullet. Shotguns use a shot shell comprising either a single bullet or a big number of small projectiles (shot or pellets). Though, the basic components of cartridges and shot shells are alike.