An introductory word or phrase should be followed by

the president was the speaker and it was a great part of history.

explanation:

video of the national aeronautic space administration's (nasa) coverage of president john f. kennedy’s address at rice university, houston, texas, concerning the nation's efforts in space exploration. in his speech the president discusses the necessity for the united states to become an international leader in space exploration and famously states, "we choose to go to the moon in this decade and do the other things, not because they are easy, but because they are hard."

the correct answer is b. in order to explain a point clearly in an essay, it is always better to include a clear example of your ideas. including an scenario in which a family is affected by consumerism will support your argument as well as supporting details, such as quotations from experts and statistics. option a could be correct, but statistics and quotations are supporting ideas rather than clear explanations. choices c and d are simply inadequate. they do not add information about the effects of consumerism, rather they are strategies for engaging the reader