The first book was written before 1985 and the plot involved a teacher and a group of high school students kidnapped by an alien spaceship while on a schoolbus. They end up in an environment on the ship that matches the Earth at the end of the Jurassic period, including dinosaurs. The most recent inhabitants before them were a starfish like people who's memories are in the ship's computer. There is an evil attachment in the computer that destroys the planet of the recent abductees' by shooting flames at it. Hence what happened to end the dinosaur age on Earth. Students and teacher must battle dinosaurs and disable computer to save Earth and themselves. Second question is a series of YA books where groups of kids compete to travel and start colonizing Mars. Written in 1980's by author who's first name is Richard, I think. Thanks