Final answer:
Giuseppe D'Amico could not find work as an electrician in Manhattan because the electrician jobs were unionized and he likely could not join the union, showing a cause-and-effect relationship between unionization and employment barriers for immigrants.
Step-by-step explanation:
The cause-and-effect relationship described in the excerpt from "Island of Hope, Island of Tears" is that Giuseppe D'Amico, an electrician by trade, was unable to secure a job in Manhattan because the electrician positions were already unionized. This signifies that the electrical trade jobs available at that time required union membership, which Giuseppe either did not have or could not obtain due to factors such as competition, possible exclusions based on his immigrant status, or other barriers that immigrant workers faced during that period.
Importantly, this reflects a broader economic and social context where immigrants, especially those who were skilled laborers, struggled to find employment due to the existing labor structures, such as unions, and the high levels of competition for jobs. It also exemplifies how many immigrants were forced into lower-paying, less skilled jobs or unemployment due to these systemic barriers.