1. 
- The changing of liquid to a gas.
2. 
- The major source of pollution.
3. 
- Carbon dioxide and water vapor trapping heat given off by Earth.
4. 
- Layer absorbing ultraviolet rays.
5. 
- The changing of a gas to a liquid.
6. 
- Layer responsible for reflecting radio waves.
7. 
- The layer in which weather changes.
The runner ran a total of 8800 yards.
Answer:
A . 6.3 In a healthy pond, the temperature is 16°C (61°F). What is the most likely pH of this pond
The classification of living things makes it easier for scientists to answer many important questions.
Examples:
-How many known species are there?
-What are the defining characteristics of each species?
-What are the relationships between these species?
