China is the country which has the largest number of hydroelectric dams. Hydropower doesn't pollute the air like power plants that burn fossil fuels, such as coal or natural gas. Hydropower is a domestic source of energy, produced in the United States. Hydropower relies on the water cycle, which is driven by the sun, thus it's a renewable power source.

Kitchen waste, leaves and fruit peels are completely organic in nature and can be decomposed naturally into simpler compounds. The simple organic and inorganic molecules add to the fertility of the soil and make it nutrient rich.
Other substances mentioned are non-biodegradable and their direct disposal into soil or water can have harmful effects. Compost is biodegradable but in this case, it is grouped with non-biodegradable substances.

The ozone depletion process begins when CFCs and other ozone-depleting substances (ODS) are emitted into the atmosphere. CFCs are extremely stable, and they do not dissolve in rain. After a period of time, CFC molecules reach the stratosphere. Due to the action of UV rays, CFCs release chlorine atoms.These chlorine atoms react with ozone molecules and destroy the ozone layer.
It is estimated that one chlorine atom can destroy over 1,00,000 ozone molecules before it is removed from the stratosphere.

Ozone at the higher levels of the atmosphere is a product of UV radiation acting on oxygen $O_2$ molecules.

$O_2$ $\stackrel{UV}{\to }$ $O$+$O$

$O$+$O_2$ $\to$ $O_3$  (Ozone) 
The sun propagates ultraviolet radiations which has an adverse effect on living beings. This layer absorbs the radiations and prohibits them from entering the outer surface of the earth.

Humans cannot digest high fibre containing substances like grass. It won't kill you, but it isn't advisable to snack on it. Human stomachs cannot digest hard raw leaves and grass easily, but cows can. This is because humans do not produce cellulose-digesting enzymes. Having a longer or a  shorter alimentary canal is not a deciding factor in this.