The gathering clouds signified that a storm was
impudent
imminent
emanant
eminent

imminent

Explanation:

It is noted from experience and also a reality that before rain falls, the gathering process of clouds first occur. After which after some time and during the process, rain falls. This shows that when the gathering of clouds occurs, rain fall is imminent. Which can lead to an unexpected event, a storm. The statement is majorly used when the situation of things would not end in a good way.

Therefore, the gathering clouds signified that a storm was imminent.

the purpose of the heading in the passage is to identify who is telling the story.

this excerpt is part of the book sugar changed the world (2010) written by marc aronson and marina budhos. as the book has been written by two people, the heading "marc" indicates that this specific excerpt is being narrated by aronson. in the fragment, marc describes his grandfather's story after hearing it from his cousin. however, there are other excerpts where budhos is the one that tells the story of her family.

aronson and budhos, who are husband and wife in real life, decided to write sugar changed the world when they found out how sugar, which had an important role in slavery and economy, changed their ancestors' lives.