There are many ways a zombie can come about as you can ascertain from the above illustration but one must be prepared for how a zombie may attack.
There are four main zombie types as illustrated below. The last one is just for fun.
1. Crawler: This is a zombie that may have been attacked by a foolish human that did not know to go for the head and instead left the zombie with only part of a body therefore it must crawl to get to brains, hence the name crawler. Easiest Kill!
2. Shambler: These types of zombies are walking on a broken leg, ankle, or foot. They are slow moving and overall just creepy. These are the most creepiest to me, I can't stand watching them shamble on that broken foot. Easy kill!!
3. Walker: These are overall slow moving zombies. They are exactly what the name says, a walker. They are easy to kill but can be dangerous in a horde (an inordinately large group of zombies that are usually drawn together by sound, ie. gun shots). Moderate kill!!!
4. Runner: These are by far the most dangerous especially when they are intelligent zombies or are in a zombie horde. Do not try to outrun them, because guess what, they never get tired!!! Weapons and intelligence work best with these types. Hard Kill!!!!
I hope that you will take my advice to heart and start to prepare for the upcoming zombie attack.