| A | B |
|---|
| nature | what can change the ecosystem? |
| ecological succession | gradual replacement of one community by another |
| how long does it take to break down rock into soil? | many years |
| what can break down rock into soil? | bacteria, fungi and algae |
| how long ago did fish disappear from the Mediterranean Sea? | six million years |
| why is strip mining harmful? | air and water pollution |
| Husker team colors | red and white |
| What are the colors of Nebraska's Friday football opponent? | black and yellow |
