Questions

Caffeine is also a psychoactive drug which alters the mood and conscious in our behaviour. It is widely consumed as a psychoactive drug.

The highly energetic gamma particles can penetrate most compounds that stop by other types of radiation. However, lead, steel, or concrete can reduce the high energy of these particles, making them less penetrating.

Hence, Gamma radiation can be stopped by a several inches of lead or steel, or several meters of concrete.

Personal flotation devices (PFDs), have life span upto it is damaged. Hence, When it has a torn strap you should discard a PFD.

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.

In music, a fugue is a contrapuntal compositional technique in two or more voices, built on a subject that is introduced at the beginning in imitation and which recurs frequently in the course of the composition. 

Hence, the main theme of a fugue is called the subject.

Nucleus serves as the control center for cell metabolism and reproduction.