Why did england feel vulnerable to attack at the end of the 19th century?

England felt vulnerable to attack because other countries were improving their militaries and growing stronger.

Explanation:

Since Napoleon's defeat in 1815, England remained the state with the greatest navy throughout the 19th century. However, the end of the century was marked by Germany rising to power, which certainly aimed at taking Britain's place. As military technology developed fast, Britain was afraid of the new advances such as aerial bombs and powerful artillery. The situation was getting more severe and eventually led to World War I.

why does the crew join ahab's quest without hesitation?

- "the basic difference between keywords and subjects is that subjects (or "subject headings") have been predetermined, while keywords have not. a keyword is an easy place to start because you can use any word that seems to fit your search; this is called "natural language" searching."