Obsidian is an extrusive rock that is formed when magma from underneath the Earth's crust breaches and becomes lava. Once the lava starts cooling, it solidifies and elements are frozen, giving the rock its glassy appearance.
Answer:
How to Make a Dichotomous Key
Explanation:
Step 1: List down the characteristics. ...
Step 2: Organize the characteristics in order. ...
Step 3: Divide the specimens. ...
Step 4: Divide the specimen even further. ...
Step 5: Draw a dichotomous key diagram. ...
Step 6: Test it out.
The body is about 55% plasma