22) To initiate nuclear fusion, a high temperature is required near the center of a star to overcome the A. electrical repulsion between protons B. nuclear force between protons C. nuclear force between neutrons D. gravitational force between all the particles E. high pressure due to high particle density

True / False Questions 23) A gravitational expansion of an interstellar cloud can be triggered by a collision with another cloud.

24) Before turning into a black hole, a star with mass 10 times the mass of the Sun will spend most of its life as a main sequence star.

25) Large interstellar clouds can collapse to form several stars approximately at the same time.

26) T Tauri stars are often observed in old star clusters.

27) In the core of high mass stars the energy is transported by convection currents.

28) Red giants are huge because their cores have expanded to a very high-density plasma.