Which choice BEST states the main idea of the passage?
There are likely many things about
echolocation that scientists have not yet
discovered.
Et
Echolocation research is important because
it has been used to develop devices such as
special walking sticks.
ea
on,
Early scientists did not have the necessary
knowledge or equipment to fully understand
echolocation.
Knowledge about echolocation and how the
process can be used to help people has
grown over time.