Answer:
1. Saw the market lose so much power that many people lost their fortunes in the matter of days --- Stock Market crash of 1929
2. Having the larger number in a house of Congress, assuring strong voting power --- Majority
3. Losing by a sizable margin in an election --- Landslide defeat
4. A person who currently holds an office --- Incumbent
5. A person who does not hold an office but who is trying to unseat an incumbent --- Challenger
Explanation:
1- The Stock Market Crash of 1929 was the most devastating fall of the stock market in the history of the United States, taking into account the global reach and the long duration of its sequels, that gave rise to the Great Depression.
2- The majority is the political group that controls a certain camera of the Congress by virtue of the greater number of representatives it has in front of other political parties, with which it exercises a de facto power over the decisions that the camera takes.
3- A landslide defeat denotes an overwhelming loss in a democratic election. For example, the Democratic defeat against Eisenhower in the presidential elections of 1952 and 1956.
4- The incumbent is the holder of a public office, in particular an electoral office.
In democratic elections, it is usually assumed that the incumbent has an official advantage; that is, the consent to his person and / or his party is greater than if he did not hold office.
5- Challenger is the one who presents himself to elections without having a political position, that is, who is not currently exercising the public office for which he is presented.