Final answer:
The word that needs to be capitalized is 'Mars' (D), as it is a proper noun referring to the name of a planet.
Step-by-step explanation:
The correct answer is D) Mars. In the sentence 'The space shuttle's mission was to journey to Mars, but the bad weather stopped the mission.', Mars is the name of a planet, which is a proper noun and should always be capitalized.
Space shuttle is a common noun describing a type of spacecraft, so it should not be capitalized unless used as part of a specific name like 'Space Shuttle Challenger'. Words like 'mission' and 'journey' are common nouns and do not require capitalization unless they are the first word in a sentence or part of a title.
The word that needs to be capitalized in the sentence is Mars.
In the sentence, 'The space shuttle's mission was to journey to Mars, but the bad weather stopped the mission,' Mars is a proper noun as it refers to the name of the planet. Proper nouns, which include the names of specific people, places, and things, are capitalized.