The Civil Rights Act of 1964 (Pub.L. 88-352, 78 Stat. 241, enacted July 2, 1964) was a landmark piece of legislation in the United States that outlawed unequal application of voter registration requirements and racial segregation in schools, at the workplace and by facilities that served the general public ("public accommodations").
The Voting Rights Act of 1965 outlawed discriminatory voting practices, such as literacy tests, that had been used in the widespread disenfranchisement of blacks.
Vetoing
Senator Strom Thurmond tried to prevent the passage of the civil rights act of 1957 by filibuster.
we can prevent smoking cigarettes by banning them from persons who owns a shop and sells them
To prevent or stall the passage of a bill.
In endodermis the passage cells passes the water molecules from the cortex to the protoxylem. Passage cells prevent the re entry of water molecules into the cortex.
shutting off a part or region to prevent passage by hostile forces
Prevent the passage of electricity to or from (something) by covering it in nonconducting material.
A guard, especially a soldier posted at a given spot to prevent the passage of unauthorized persons. Very true, soldiers during the first world war were on sentry duty for up to two hours before another soldier took over.
Let's take something obvious. Where would a crowd of persons move faster? Where there is absolutely nothing to prevent their passage or where there is an open gate? The same thing applies to the movement of ions. Movement of ions through ion channels is a slower process because (with a more scientific approach!) their movement is determined by the number of these ion channels whereas for diffusion, there is absolutely nothing to prevent the passage of the molecules.
to prevent a nationwide railroad strike
To prevent anyone from consuming any alcoholic beverage.
They are variable controls which can open to allow the passage of material and then closed to prevent further passage of materials. If you didn't have an anal sphincter you'd really have problems.