Cassava is a plant product used to make biodegradable plastic. Tapioca is a starch extracted from cassava.  In India, the term tapioca is used to represent the root of the plant (cassava), rather than the starch. Tapioca root can also be used to manufacture biodegradable plastic bags. 

Some ponds look green from a distance because of the excessive growth of algae. The excessive growth of algae being green in color gives a false impression that the pond is green from a distance. 

'A lot of carbon dioxide is used in the process of decomposition and its decreasing level kills aquatic organisms' is an incorrect statement. Phosphorus and nitrogen combined with carbon dioxide are the main supplies that can turn your pond from clean to green very quickly. All aquatic plants and algae make their own energy through photosynthesis which uses sunlight and carbon dioxide to create energy and oxygen as the byproducts. Carbon dioxide released in the process of photosynthesis is used in aerobic decomposition. 

The 1987 Montreal Protocol was signed to phase out the use of CFC's, found to be causing depletion of the ozone layer. The Montreal Protocol on Substances that Deplete the Ozone Layer is an international treaty designed to protect the ozone layer by phasing out the production of numerous substances believed to be responsible for ozone depletion. 

A river said to be ‘dead’ when the river becomes highly polluted to sustain aquatic life. 

The function of a water treatment plant is that. It acts upon the harsh chemicals and toxic materials which are present in water and converts them into less toxic and easily decomposable materials. They pump in raw untreated water from a well, lake or river. Remove the odor and bad taste by aeration remove settable solids, disinfect the water, adjust the PH of the water, filter the water, then pump it out for your use. 

Above the ozone layer, a layer of ions is present, which does not reflect ultraviolet rays, X-rays or infrared rays. While both oxygen and ozone together absorb 95 to 99.9% of the Sun's ultraviolet radiation, only ozone effectively absorbs the most energetic ultraviolet light, known as UV-C and UV-B.  

Zn is a micronutrient. Micronutrients such as boron (B), chlorine (Cl), copper (Cu), iron (Fe), manganese (Mn), molybdenum (Mo) and zinc (Zn) are essential for plant growth. If the micronutrient supply is insufficient, plants may develop deficiency symptoms and yields may be reduced. 

Radioactive substances can pollute Earth to dangerous levels of toxicity if not handled properly.

The atmospheric layer of ozone normally absorbs more than 99% proportion of UV radiation from the sun.

Due to water cycle, the amount of water on Earth remains more or less the same.

Silviculture was initiated for replenishment of forests. Silviculture is used due to the speed of its growth and the value of its timber and is frequently used in replanting and forest control efforts. This field of study is concerned with the regular replenishment of forests, using a variety of tactics like clear-cutting and group selection. 

D.D.T. is an example of non-biodegradable substance. It is a colourless contact insecticide, C₁₄H₉Cl₅, toxic to humans and animals when swallowed or absorbed through the skin. It contains pesticides. Substances that are not broken down by biological processes are called non-biodegradable substances. 

Trees give out large amount of water by the process of transpiration. 

The gas which leaked from the Union Carbide Plant in Bhopal in 1984 was methyl isocyanate. 

Ozone layer is a sub layer of Stratosphere. It is in the lower stratosphere, from 6 to 25 miles above the ground. There is also ozone present in the lower troposphere, but the ozone layer in the stratosphere contains helpful ozone that blocks much of the Sun's ultraviolet radiation. Without this layer, life on earth would be very difficult. 

Water is a renewable source of energy. Water flowing downstream is a powerful force. Water is a renewable resource, constantly recharged by the global cycle of evaporation and precipitation. The heat of the sun causes water in lakes and oceans to evaporate and form clouds.  

Wildlife is necessary for ecological balance. The balance of nature is a theory that says that ecological systems are usually in a stable equilibrium. It may apply where populations depend on each other, for example in predator/prey systems, or relationships between herbivores and their food source. 

Rise in the sea level and regional climatic changes are the two major impacts expected, as a result of rising global temperatures. An increase in global temperature will cause sea levels to rise and will change the amount and pattern of precipitation, as well as cause a probable expansion of subtropical deserts. 

The water cycle in nature is called Hydrological cycle. the water cycle, also known as the hydrological cycle or H₂O cycle, describes the continuous movement of water on, above and below the surface of the Earth. Water can change states among liquid, vapor, and ice at various places in the water cycle. 

Deforestation leads to Soil erosion, less rainfall and frequent floods. As plants and trees play an important role in water cycle so deforestation leads to disturbance in water cycle. This results in frequents floods and less rainfall.  Also Deforestation loosens up the soil which leads to soil erosion. 

Monoculture decreases the fertility of the soil. As same crop is grown every year which leads to decrease in organic matter and CEC due to which soil fertility decrease. Also it has some negative impacts on its structure, in the aeration and in biological activity among other phenomena. 

Monoculture means growing the same crop in the same soil year after year. Monoculture is the agricultural practice of producing or growing a single crop or plant species over a wide area and for a large number of consecutive years. It is widely used in modern industrial agriculture and its implementation has allowed for large harvests from minimal labor. 

Coal is not a non-conventional source of energy.  Coal is very widely used as a source of energy. It provides employment to over 7 lakh workers. Its reserves are substantial. Coal has a favour over other fuels as it can be converted into other forms of energy. 

World wide fund for nature's study found that Ganga is one of the ten most endangered rivers. The World Wide Fund for Nature (WWF) is an international non-governmental organization working on issues regarding the conservation, research and restoration of the environment. According to an assessment made by this organization Ganga is an endangered river.