Answer:
Adaptation
Explanation:
Some beaks made it easier for the type of food that bird was trying to get, for example the sharper the beak the better it could possible break a nut

The answer is...
B. Cooling as the lava runs down the mountain.
Hopefully, this helps you!!

Answer:
Control group remains unchanged.
Explanation:
For example if you are trying to see if watering plants with Pepsi is better.
Your experiment plant would get watered with Pepsi.
Your control plant would get watered with water. (Control groups serve as a reference to compare in the experiment)