The Arabian Peninsula became a center for trade between India and Europe because:
A. it was located between two large seas.
B. it was home to the wealthy Bedouin people.
C. it got very little rain for most of the year.
D. its moneylenders did not charge interest.

Ascientist performs an experiment where she measures the mass of a piece of metal, pours acid onto the metal, washes the metal, and then re-measures the mass of the metal. the scientist repeats the experiment several times, each time increasing the amount of acid used. the dependent variable in the experiment is the: initial mass of the metal final mass of the metal amount of acid used washing the metal