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	% white moths	% black moths
1910	95	5
1920	95	5
1930	95	5
1940	50	50
1950	20	80
1960	5	95

If a seed from one of the trees was planted in an area far from the steel mill, what color would the bark of the tree be?

• A. Black, because the parent tree had black bark
• B. White, because the gene causing black bark was mutated due to environmental pollution
• C. Black, because the gene causing white bark was mutated due to environmental pollution
• D. White, because the black bark was an acquired characteristic and is therefore not passed on to progeny
• E. The color of the bark is not able to be determined.

Answer 1

The correct option is D White, because the black bark was an acquired characteristic and is therefore not passed on to progeny

White, environmental change caused the darkening of tree bark which was then maintained over ten years. Since darkening of tree bark was caused by pollutants, it is an acquired factor, not a genetic one. So, seeds will grow into tree having white bark and the bark will turn black by prevailing pollutant.

Therefore, the correct answer is option D.