So what are your thoughts? How did mark Die?

I am going to say Car wreck...

Car wreck
Motorcycle accident
can't forget that Mark owned a motorcycle a triumph which was never mentioned but it was one of the reasons Dan at first didn't like him because of his choice in motorcycles.

Becky and Mark will always be my fav couple ....i skip the episodes with sarah chalke as becky. Glenn and Lecy had more chemistry. Even when Lecy came back in S8.

It was revealed in Season 3 of The Conners that Mark died in a motorcycle accident when a deer jumped out in front of him.