In the context of european colonization, portugal controlled mozambique and
a. madagascar.
b. angola.
c. kenya.
d. congo.

might be agreeing to participate ethically with other european nations in the slave trade

or notifying other european nations when taking possession   of african territories

the answer is b: the religion they practice.

here's why:

there were many different native american tribes and those with similar characteristics formed a main tribe or nation. each had its own language, religion and customs.