Answer:
The ozone layer is being depleted due to CFC's. CFC's are found in aersoal spray cans and refrigants, when they are released into the atmosphere it causes depletion of the ozone layer. Humans are the one who made the CFC's, causing the ozone layer to deplete, even though they have been banned now, a lot of damage has been done.
Answer from Gauthmath
Light disappears entirely. Sunlight is unable to penetrate that deep, which is why many fish have adapted to produce their own light.
The part of the mushroom that you can see above the ground is actually a fruiting body. The correct answer is A, fruiting body.