1. Which of the following statements correctly describes pulsating stars? A. The core of pulsating stars expands and shrinks rhythmically B. They lie between the blue giants and the red giants in the H-R diagrams C. Their temperature and radius change rhythmically D. All of the above E. Both B and C 2. 15. In the H-R diagram a T Tauri star will be located ____. A. Near the upper right corner B. Near the upper left corner C. Near the bottom left corner D. Below the main sequence E. On the right hand side and a little above the main sequence. 3. The CNO cycle produces energy by fusing _____ into ____. A. Oxygen; nitrogen B. Hydrogen; helium C. Carbon; helium D. Helium; carbon, nitrogen and oxygen Solution 1 . D .all the above ( actually all the options are right about pulsing stars ) 2. E. On the right hand side and little above the main sequence. 3. B. Hydrogen to Helium.