What caused conflict between the africans and the boers?

a.
the boers stole the africans’ cattle.

b.
the africans had to pay tribute to the boers.

c.
the boers took land away from the africans.

d.
the africans were angry that the boers kept slaves.

You have been tasked with sorting the rock samples shown into three categories, with two rocks in each category. what attribute would you use to sort these rocks? which rocks would be in each category? rocks: obsidian, coquina limestone, granite, soapstone,pumice, and gneiss.