Answers - Plate Boundaries

1. Divergent, convergent, and transform plate boundaries

2. Divergent means to move away which involves plate movement because the plates pull away from each other. The plates move by magma pushing up from the mantle.

3. Mid-Atlantic Ridge. Iceland sits on it. The triangles are Iceland's active volcano.

4. Convergent means coming together so for plates, they come closer together and one ends up diving under another.

5.
a. Oceanic-continental convergence

b. Oceanic-oceanic convergence

c. Continental-continental convergence

6.
a. Deep sea trenches and volcanic arcs
b. Deep sea trenches and island arcs
c. Very high mountains

7. Transform boundaries is when plates slide horizontally past each other but crust is not produced or destroyed. It causes shallow earthquakes. An example of one is the San Andreas fault in California.

8.
a. Divergent boundary and 2 oceanic plates make it happen.
b. Convergent boundary and also 2 oceanic plates are here.
c. Convergent boundary and also 2 oceanic plates take place here.
d. Divergent boundary and 2 continental plates.
e. Divergent boundary and 2 continental plates.
f. Convergent boundary and the 2 plates are oceanic-continental.
g. Convergent boundary and the 2 plates are oceanic-oceanic.

Geologic Timeline: Follow-up Questions

Scratch off the second answer.

The Archeaen Eon is the most important because that's when the first cyanobacteria appeared, not the Proterozoic. The Earth is also done it's stratification and the crust was formed. The first cyanobacteria and the first oceans that began to form lead to the start of multi-cellular life.

Geologic Timeline: Follow-up Questions

1. The Earth had to have been solid and not molten. The Earth's oceans had to have formed. The first bacteria had to have shown up and the Earth's atmosphere had to have oxygen in it. Organisms with the ability photosynthesis had to have appeared. After there were plenty of single cell organisms they could have evolved and split into multi-cellular organisms.

2. The Proterozoic Eon was the most important in terms of the development of the Earth because the first cyanobacteria appeared and the Earth's atmosphere began to fill with oxygen which lead to the start on multi-cellular life.

3. The presence of humans is not that significant in context of the entire history of the Earth. The humans history is minuscule compared to everything else. Because of that humans didn't play a big enough part to the Earth's history. If anything it's the other way around. The Earth's history is very significant to the presence of humans.