For centuries, arab muslims had generally welcomed christian pilgrims to the holy land. which group later took control of the holy land, attacked pilgrims, and led pope urban to call for the crusades?
a. mongols
b. byzantines
c. seljuk turks
d. north africans

Ascientist is explaining how background cosmic radiation gives evidence of the big bang theory. she says that radiation has been detected everywhere equally as heat in the universe and is increasing. this has been shown to be residual radiation from the big bang. what error did the scientist make?