Which of the following scenarios represents change to an ecosystem brought about by biotic factors?

a. a wildfire caused by lightning striking a tree
b. a flood caused by a severe storm

c. a landslide caused by cattle overgrazing

d. a volcano

The earth is composed of three different chemical layers: core, mantle and crust. the formation of these layers was from a process called

In the scramble for africa, european powers drew boundaries and created states that benefitted the colonizers while ignoring the needs of the local populations. what effects did this policy have on the indigenous people following independence?

Most of the volcanic activity that occurs in the ring of fire is a result of the a. formation of mantle plumes away from plate boundaries. b. subduction of one plate under another. c. movement of two plates away from each other. d. sliding of one plate past another.