Question

Read the following passage and answer the following question.
In 1910, a small town on the East Coast of the United States relied primarily on agriculture to support its economy. In the mid-1930s, a steel mill was built, and the economy shifted from being agriculturally supported to being industrially supported. The steel mill released a lot of smog and soot into the air, which collected on the bark of trees in a wooded area near the outskirts of town. Over a period of ten years the bark gradually darkened, then maintained a constant dark color. A variety of animals and insects lived in the wooded area. In particular, a certain species of moth served as the primary food source for a population of birds. The moths lay their eggs in the bark of the trees and, thus, must spend a fair amount of time sitting on the tree trunks. Table 1 presents data on the moth population.Table 1

Year	White moths (%)	Black moths (%)
1910	95	5
1920	95	5
1930	95	5
1940	50	50
1950	20	80
1960	5	95

Birds track their prey visually, whereas bats rely on sonar to locate to locate their food. If the bird population were replaced with a bat population in 1940, what would be the ratio of white moths to black moths?

• A. 95% white, 5% black
• B. 80% white, 20% black
• C. 50% white, 50% black
• D. 20% white, 80% black
• E. 5% white, 90% black

Answer 1

The correct option is C 50% white, 50% black

Bats prey using sonar to locate their food and color differentiation of white and black moth would not impart any survival advantage to them. This will result in no change in the ratio of white and black moth population. Thus, the correct answer is option C.