Questions

Town planning, Drainage system and Use of Bronze are the features of Indus Valley Civilization. Use of Iron was not the feature of this.

Secondary pollutants include ozone, which is formed when hydrocarbons (HC) and nitrogen oxides (NOx) combine in the presence of sunlight.

Whereas Primary pollutant are those pollutants that are directly emitted from their sources, like CO2, CO, SO2 as these gases are directly emitted form burning of fossil fuels.

Acid rain, which is formed when sulfur dioxide or nitrogen oxides react with water, sulfuric acid etc.

Hence, Acidrain is a secondary air pollutant.

M=P(1+i/365)^365n

The Civil Rights Movement :

The Civil Rights Movement in the United States was a struggle by black Americans to gain full citizenship rights and achieve racial equality.

Individuals and organizations challenged discrimination with a variety of activities, including protest marches, boycotts, and refusal to abide by segregation laws.

Many believe that the movement began with the bus boycott in Montgomery, Alabama, in 1955 and ended with the Voting Rights Act of 1965.