In a longitudinal wave, the motion of the medium is parallel to the direction of the wave. This means that the particles move left and right which in turn makes the other particles start to oscillate.
The UNIA founded by Marcus Garvey has a constitution which defines red, black, and green as the Pan-African colours: red representing the noble blood that unites all people of African ancestry, the colour black for the people, green for the rich land of Africa..
Meaning of the flag of Democratic Republic of Congo: The colors green, yellow and red are the traditional Pan-African colors: green symbolizes agriculture and forests; yellow symbolises the friendship and nobility of the people; red stands for the struggle for independence.