Which of the following scenarios demonstrates the replication of a scientific investigation? A.
Dr. Kim performs an experiment in her laboratory. Then, Dr. Stevens performs the same experiment in his laboratory to verify the results.

B.
Dr. Abraham performs the same experiment in his own laboratory on five different occasions.

C.
Dr. Jordan visits another scientist and watches the scientist perform an experiment in her own laboratory.

D.
Dr. Burgess reads about an experiment in a scientific journal. He performs a similar investigation in his own laboratory, but he changes some of the variables.

for many centuries there were important factors which the economies of the muslim empires developed increasingly. they applied economic procedures in production, investment, finance, taxation and property. they used to tax certain goods (for example: harvest), they charged interest on money lent, they signed contracts with merchants; they relied on a common currency, and they used checks as well as promissory notes. with the money collected by means of taxation, the government provided the needy with an income. in addition, trading networks covered huge distances, so far regions started to have contact and exchange goods. this trade network covered areas of asia, africa and europe.