HI Michelle,
My sons love the Disney's Animal Kingdom because of
Expedition Everest, one of their favorite rides. I would describe it as more intense than the Magic Kingdom mountain rides, but not as intense as Mission Space, Tower of Terror, and Rock 'n Roller Coaster. It does go quite high (beautiful views, though), goes backwards, feels like you go upside down, and is in the dark. There is also a large Yeti that swoops down at guests.
Dinosaur is also a bumpy ride with one big scary moment toward the end. We have lots of pictures of our family with our sons curled up against us with their eyes shut. I think it does help to have seen the movie before to understand the background and characters better.
Primeval Whirl is a light-hearted, slightly campy attraction that my kids really enjoy, but it makes me very queasy with the spinning it does throughout the ride.
Kali River Rapids is the other thrill ride at Disney's Animal Kingdom that can be unpredictable as you ride on the water. I've come out soaked head to toe and come out bone dry. What I find intense about the ride is when you are going backwards and not knowing if you are about to get soaked.
The tricky part of describing the intensity of attractions is that it can truly vary from guest to guest. What terrifies one guest may make another smile. If you visit Youtube, there are videos of many of the attractions, which may help you to make a better decision.