What makes a source credible is it has backed up information. Basically, it has to have supporting details so you know its true.
"Nuclear atom" or "planetary model of the atom".
The key word it here is each which means multply
Answer:
Along the coast of North Africa sea port cities developed such as Marrakesh, Tunis, and Cairo. The port city of Adulis on the Red Sea was also an important trade center. The major trade routes moved goods across the Sahara Desert between Western/Central Africa and the port trade centers along the Mediterranean Sea.
White expansion. War between Indians and the whites was very common because the whites seemingly had quite an appetite for the Indian land. Indians struggle to contain this aggressive expansion led to war with hope to reduce American settlement and expansion.