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Ozone is a molecule formed by three atoms of oxygen, which shields the surface of the earth from ultraviolet radiations.

Waste Combustion is the process of burning waste at very high temperatures. It is the simplest and earliest form of waste disposal. But this method leads to the release of highly toxic chemicals in the environment which is harmful to the organisms.

Chlorofluro Carbons.

(A) (ii), (iii) and (iv) only 

CFCs are chlorofluorocarbons are the synthetic chemicals which are made by humans artificially, that means they are not the natural products. Excessive use of these CFCs in refrigerators, ACs, fire-extinguishers, etc. causes the depletion of ozone layer. Because then UV radiations will reach the earth’s surface destructing the survival of plants and organisms.

(i) The full form of : 

(a) UNEP: United Nations Environment Programmes.

(b) CFCs : Chlorofluorocarbons. 

(ii) Organisms can be grouped as producers, consumers and decomposers according to the manner in which they obtain their food from the environment.

(iii) Two problems that would arise in absence of decomposers in an ecosystem are : 

(a) Decomposition of garbage as well as dead plants and animals will not take place.

(b) Natural replenishment of soil will not take place.

Effects of the depletion of the ozone layer: 

1.1 On human health-Skin Cancer 

Today, it is estimated that skin cancer rates increased due to the decrease in stratospheric ozone (ozone layer). The most common type of skin cancer is the cause of exposures to UV radiation from sun.

2. Effects on aquatic ecosystems 

The loss of phytoplankton, the basis of the marine food chain, has been observed as the cause of the increase in ultraviolet radiation. For example: Under the ozone hole in the Antarctic phytoplankton productivity decreased between 6 and 12 percent. That disturbs the ecosystem.

Correct option  (B) (i) and (iii) only 

Explanation:

 A food chain does not show branching lines. It is always straight and proceeds in a progressive straight line. Usually a food chain consists of three or four trophic levels but in few food chains, there may be a maximum of five trophic levels.

Two reasons for the conservation of the environment:

(a) (i) To save air, water and soil from pollution.

(ii) To maintain ecological balance in nature.

(b) Green dustbins for biodegradable waste, and blue dustbins for non-biodegradable waste are meant for proper disposal of waste without wasting time and energy in segregating the biodegradable and non-biodegradable wastes.

(c) Values: cooperative spirit, concern about environment, civic sense or any other.

CFCs are manmade chemicals called chlorofluorocarbons. These substances are found in refrigerators, ACs. Etc. Due to long life and their ability that they do not wash in the rain, so they rise up into the ozone layer above the earth, where they eventually breakdown by heavy exposure to ultraviolet (UV) radiations. When CFC is broken down, it releases chlorine and bromine atoms which can destroy various ozone molecules at once. They cause the ozone layer to breakdown faster than it can replace itself.

The Correct option is (D)  

(a) Planting trees, reducing the use of non- renewable sources of energy, saving water, proper garbage disposal, less use of chemicals, cleaning society.

(b) (i) The members appreciate the fact that rational use of natural resources is their responsibilities towards saving the nature for future generations as well.

(ii) Members are nature lovers and eco-friendly.

It is because waste has to be disposed in such a manner that it doesn’t cause any type of pollution. For example: When wastes are dumped into water bodies they pollute it and also affect the marine life. If it is buried in soil, it will cause depletion of the fertility of the soil and makes the land a waste land. Hence proper disposal of waste is important because:

a) Garbage can be a source of diseases. 

b) It can be processed to recycle useful components. So, garbage should also be disposed at proper places. 

c) Some garbage contains plastic which can harm our environment. So they should be disposed after taking proper care.

Correct option  (D) lncineration

Explanation:

 lncineration is the process of burning substances under aerobic conditions at high temperature (usually more than- 1000°C) in a closed unit called incinerator.

(i) Due to large scale removal of frogs, the population of frogs got reduced in the village. Due to absence of frogs in food. chain, grasshopper/mosquitoes - frog - snake' the population of grasshoppers and mosquitoes have gone up. Mosquitoes are the carries of malaria vector and grasshoppers damage the crop.

(ii) Every organism has a very important  role in nature and we should not disturb this food chain artificially. if one link is removed from the food chain, whole chain gets disturbed and new problems arises.

(iii) I will request him not to renew his contract for supply of frogs with the colleges. This will increase the frog population and population of mosquitoes and grasshoppers will decrease and a balance will be attained soon.

I do not agree. 

As an individual, I also have the responsibility and can contribute in the following ways : 

(i) Cut down waste generation. 

(ii) Make compost pit for bio-degradable waste. 

(iii) Recycle non-biodegradable waste.

The food chain in the given situation will be:
Phytoplankton ----> Zooplankton ---> Mosquito larva ------> Frogs
In the absence of frogs (as they were exported), more mosquito larvae survived giving rise to large number of mosquitoes. The large number of mosquitoes caused increased incidences of malaria.

• Decomposers breakdown dead and decaying living matter and helps in the nutrient recycling. 
• This will clean the environment by removing dead material.

Answer is (A) Biomass

a) Environment 

b) Trophic level 

c) Abiotic factors 

d) Consumers or heterotrophs

• Substances which can be broken into pieces by biological process are known as biodegradable substance. 
• Substances which cannot be broken into pieces by biological process are known as non-biodegradable substance.

Difference between biodegradable and non- biodegradable substances :

Two methods of disposal of non-biodegradable waste are:

(i) Recycling : The wastes are treated and same value materials are extracted for reuse.

(ii) Incineration : Medical and toxic waste are burnt at high temperature in incineration. Incinerators transform the waste into ashes.

People should adopt following changes in habit:
(a) Dispose household waste, chemical waste and hospital waste in a landfill.
(b) Broken plastic articles such as buckets, bowls, cups, plates, etc., should be sent to plastic processing factories.

(D) (i), (ii), (iii), (iv) and (v)

(C) (a)-(iv), (b)-(iii), (c)-(ii), (d)-(i) 

Biodegradable waste products are changes in agricultural resources like fertilizers. These biodegradable substances can be broken down by biological processes (like by enzyme or bacterial action). For Examples: cattle dung, cotton, jute, paper, fruit and vegetable peels, leaves etc.

They can be used as various agricultural resources, for example: 

a) Cattle dung is used as natural fertilizers for crops and plants. It is also cost-free. 

b) Jute can be used to prepare bags for storing grains. 

c) Vegetable peels can be used as food for cattle’s. Etc.

Plants are the only living organism that can consume energy from sunlight to prepare food with the help of a process called photosynthesis. They are the primary producers of every ecosystem. And they are always the largest in number because there have to be more food producers than consumers, to sustain life on earth.

Because of lack of regulation, some amount of highly toxic pesticides got in the beverages consumed by people day to day. If ingested over long periods, these chemicals could lead to cancer and failure of the immune system.

Paper is made from trees, and every single part of the tree is either chopped up to make products or burned to create energy. Although paper waste is biodegradable it’s recycling adds more advantage because decomposition takes time(some months or years) but recycling can be done in just some hours. 

Paper recycling is a simple process which leads to the recovery of waste paper and converting it into new paper products. Recycling old paper products uses 60% less energy than manufacturing it from new materials, as it would save a lot of trees from being cut down.

Ecosystem is the interaction of living things with themselves and with the surrounding environment. It's functions in 4 main aspects: 

1. Productivity- there should be a balance between the amount of food produced and consumed. 

2. Decomposition- The dead and decay matter has to be decomposed successfully to replenish the environment with nutrients. 

3. Energy flow- the transfer of energy from one trophic level to another has to follow 10% rule to sustain life. 

4. The nutrient cycling- the connection of various components of the ecosystem should be proper to get back the depleted nutrients in the environment.

When we dispose of them in a garbage pile, the air, moisture, climate, or soil cannot break them down naturally to be dissolved with the surrounding land. They are not biodegradable.

Some practices are: 

● Throwing of plastic water bottles and plastic bags. 

● Metal scarps improper disposal. 

● Construction waste, rubber tires, man-made fibers like nylon etc. 

● Useless computer hardware like glass, CDs, DVDs, cellophane, processed woods, cable wires, etc.

Decomposers are micro organisms that obtain energy from the chemical breakdown of dead organisms of animals or plants. These micro organisms breakdown the complex organic substances of dead organisms into simple inorganic substances that go into the soil and are used up once more by the plants. Decomposers thus, help in recycling of matter.

Because after that the energy available for the next organism will be so small that it will be insufficient to sustain the life of that organism.

1. a. Incineration

2. b. Land fillings

3. d. they are made up of non biodegradable materials

4. b. Grass, wood, plastics

5. c. Composting

1. d. Population of tiger decrease and grass increases

2. a. food web

3. b. Grass, goat and human

4. c. A and B

5. b. Trophic level

Aquarium, Garden, Terrace Garden, zoological park.

Natural ecosystem can be broadly classified into two types. They are ; 

1. aquatic ecosystem 

2. terrestrial ecosystem.

1. Organism : Any form of life can be called as organism. 

2. Species: Species is a group of similar organisms sharing common genetic structure and capable of breeding among themselves. 

3. Population: A collection of individuals belonging to the same species occupying a given area at a given time is called population. 

4. Biotic components : The living components are called biotic components. 

Eg: plants, animals, bacteria, and fungi. 

5. Ecosystem : An interaction between living and non-living components is known as ecosystem. 

6. biotic component : The non¬living components are called as biotic components. 

Eg : Air, water, land, sun, light

The materials which are used for energy production are known as biofuels.

If the producer is a large plant such as tree or if one of the organisms at any tropic level is very small, then the pyramid of number does not look like a pyramid.

In a pyramid of number, each bar represents the number of individuals at each tropic level in a food chain.

Pyramid of number shows the population of organisms at each tropic level in a food chain.

A graphical representation designed to show the number of organisms at each tropic level in a given ecosystem is called “pyramid of number”.

The producers are represented at the base of the ecological pyramids.

Green plants is an example of producers.

Cow  is an example of herbivores.

Plants is not an example of abiotic factors.

(d) Chlorofluorocarbon

1. The heavy metals could find their way into human beings through food chain. 

2. This bioaccumulation cause various physiological disorders such as hypertension, sporadic fever, renal damage, nausea etc.

Man is at the top of most food chains and hence, due to biological magnification there are greater chances of accumulation of harmful chemicals in the body.