1. Which stellar spectral type is most likely to have a planet on which advanced life exists? a. O b. B c. A d. G e. M 2. Which element serves as the foundation or “backbone” of life? a. oxygen b....

1. Which stellar spectral type is most likely to have a planet on which advanced life exists? a. O b. B c. A d. G e. M

2. Which element serves as the foundation or “backbone” of life? a. oxygen b. carbon c. silicon d. hydrogen e. nitrogen

3. What arguments could you make against sending messages via radio or spacecraft into interstellar space?