Ageologist finds that the number of fossils in a rock layer had significantly fewer fossils of all types than the layers above and below it.

which is the best conclusion?

a.
some type of mass extinction event occurred during this time.

b.
the rate of sedimentation changed during this time.

c.
an asteroid impacted the earth during this time.

d.
the earth's magnetic pole shifted during this time.

Which of these statements describes a long-term impact of european imperialism in africa? a. african countries joined together to present a united front against imperialism. b. europeans paid african countries after colonizing them, offering these new countries a fresh start. c. european powers drew the current borders, splitting ethnic groups among modern countries. d. africans became more loyal to their countries than to their ethnic groups.