Question

review the details below.

• as an astronomy and space sciences professor at cornell university, dr. carl sagan edited a scientific journal, published books, and appeared frequently as a guest on late - night talk shows.
• dr. carl sagan wrote a highly popular companion book for the series cosmos, as well as the follow - up book pale blue dot: a vision of the human future in space.
• dr. carl sagan was the co - host and co - writer of cosmos: a personal voyage, a thirteen - part pbs series watched by 750 million people.

choose the best topic sentence to introduce a paragraph containing these details.
dr. carl sagan used his credibility as an academic to co - host and co - write cosmos: a personal voyage.
tv series and books designed for the average person are the best ways to get the public interested in scientific topics.
dr. carl sagan was a gifted communicator who used his vast knowledge to share scientific topics with millions of people.

Explanation:

The details mention Dr. Carl Sagan's academic role (professor), his work in different media (editing journal, writing books, appearing on talk shows, co - hosting and co - writing a TV series). The first option only focuses on one aspect (co - hosting and co - writing Cosmos). The second option is too general about TV series and books in general. The third option encompasses his role as a communicator (through various media like books, TV, talk shows) using his knowledge (as an academic) to reach millions (750 million for Cosmos).

Answer:

Dr. Carl Sagan was a gifted communicator who used his vast knowledge to share scientific topics with millions of people.