Question

read the passage.
sign language on marthas vineyard
while researching marthas vineyard, an island off the coast of massachusetts, anthropologist nora groce made a remarkable discovery. she learned that from the 1600s until the early 1900s, almost all the residents of two towns on the island—west tisbury and chilmark—were fluent in sign language. during these years, the towns had an unusually high population of deaf people, due to a form of hereditary deafness that ran in many marthas vineyard families. consequently, a bilingual society developed. the islanders didnt attend special sign language classes; they simply learned the language as they grew up. one of the most interesting aspects of the phenomenon was that, in the absence of language barriers, deafness was not perceived as a disability. as one vineyarder explained to groce, deaf people were seen as \just like everyone else.\
what is the main, or central, idea of the passage?
the high incidence of deafness on marthas vineyard led to the development of a bilingual society.
the large population of deaf people on marthas vineyard was due to hereditary deafness.

Explanation:

The passage first introduces anthropologist Nora Groce's discovery about Martha's Vineyard. It states that from the 1600s to early 1900s, two towns had a high deaf population due to hereditary deafness, which led to a bilingual society (residents fluent in sign language) and deaf people not being seen as disabled. The first option captures the main idea as it connects the high deafness incidence to the development of the bilingual society. The second option only explains the cause of the large deaf population, which is a supporting detail, not the main idea.

Answer:

The high incidence of deafness on Martha's Vineyard led to the development of a bilingual society.