The greatest geographic obstacle to the spread of islam in the 7th century was
a)
river systems.
eliminate
b)
the indian ocean.
c)
expansive deserts.
d)
dense rainforests.

the lachish letters were written by hoshaiah, a military officer stationed possibly in mareshah,   and sent to yaush, possibly the commanding officer at lachish.

the series of letters were written in carbon ink in ancient hebrew on clay ostraca, shortly before lachish fell to the babylonian army of king nebuchadnezzar in 588/6 bc during the reign of zedekiah, king of judah.

the correct answer is c sinners in the hands of an angry god.