Healthy Ecosystems I believe
The answer is cell. In the cell level of organization arachnoidiscus enhrenbergii and the stomach can be seen.
The speed of a longitudinal wave will not be affected by the temperature of its surrounding. Base on the formula for the wave speed (applicable on longitudinal wave), wave speed ( speed in m.s 2) is equal to the distance of a wave (wavelenth in meter) travel over a unit of time (seconds) or wave speed is equal to distance of a wave times the frequency (hertz), temperature is not included in calculating the wave speed.