The answer is:
d) the sound originates from a vibration.
The explanation:
The sound waves are generated by a sound source, such as the vibrating diaphragm of a stereo speaker. The sound source creates vibrations in the surrounding medium. As the source continues to vibrate the medium, the vibrations propagate away from the source at the speed of sound, thus forming the sound wave.
I believe it’s density and temperature
I don't really know what it's about but everything looks okay to me. There might be some mistakes on the last sentence but i'm not completely sure.
Answer:
a) 35.44 mm
b) 17.67 mm
Explanation:
u = Object distance = 3.6 m
v = Image distance
f = Focal length = 35 mm
= Object height = 1.8 m
a) Lens Equation

The CCD sensor is 35.34 mm from the lens
b) Magnification


The person appears 17.67 mm tall on the sensor
He needs to measure when he draws the Simpson characters to make sure they are the same time each time he draws them