Answer:longitudinal design
Explanation: we need to know what is longitudinal design. By definition,
longitudinal design is the study of variables or group of variables which have similar cases and repeated over a long on short period of time. This cases happened between a similar group( teenage girls ), and it happened repeatedly over a long period of time, so this will require a longitudinal design.
Answer:
The third diagram shows Refraction of waves.
Explanation:
Refraction is a phenomenon, which occurs in a wave when it travels from one medium to another medium, and during Refraction there is slight or greater change in direction of the wave.
hence, the wave will pass through the surface and displaces from its actual path.
that's why the most appropriate diagram showing Refraction is third one ( c ) .
A physicist term for the measure of the amount of disorder is ENTROPY.