Im not sure if this will be the answer you teacher is looking for but i think the answer would be
Hair on the head protects scalp from injury and sunlight
Eyelashes and eyebrows protect eyes
Nostril and ear hairs protect from foreign particles
1. natural selection acts on existing traits because you can not evolve into something you didn't have
2. original structures evolve to accomplish new function in order to survive
Answer:
Industrial Revolution
Explanation:
In the 18th century, the industrial revolution took place. People started having more jobs than before and also getting paid for their labor. As the workers and employees were getting paid and jobs were available because of the industrial revolution, people started buying goods for their families. As a result, the standard of living also went up. Also, there was enough food for families to grow. As a result, the total population increased. In the 18th century, for the first time, the total population reached 1 billion landmarks.
Irrigation system gave the ancient civilizations fertile land which helped crops grow. It also allowed for ease of watering which made the process of farming faster.