The answer is
C. periodic fluctuations in the intensity if sound waves.
4. Grass - Caterpillar - Hedgehog - Fox
5. Caterpillar, Rabbit, Mouse.
6. Cougar and Fox.
7. Bacteria
8. The bird, hedgehog, Fox and cougar would be effected since the Hedgehogs and birds would soon die out due to the loss of their food. Once they die out, the cougar and Fox would have no predators left to eat.
This would be a cryogenic intermodal tank. These are used to store and transport HAZMAT gases that require storage under specific pressure and temperature parameters. Cryogenic Intermodal tanks have pressure of 25 Psi or less.