8. Ang sistema ng pakikipagkalakalan na ginamit ng ating mga ninuno na kung saan ang mga produkto ay ipinapalit sa ibang produkto na dala ng
ibang lahi.
A. Kaingin
B. Barter
C. Pagmimina
D. Pangangayaw
answer me please
correct answers only

13) q: a: when world war i began, the official united states policy was

Which statement about african americans during the civil war is true? o a. they were granted the vote in the north. o b. they were allowed to attend northern universities. c. they were given deeds to southern plantations. o o d. they enlisted in the union army.

Search america's open door policy with china beginning in 1899. explain how relations with the united states and china have changed and the effects of the open door policy on both countries.