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The third trophic level is occupied by the II consumer. II consumers are carnivores which feed on herbivores or grass eating animals. Carnivores are tiger, wolf, etc.

Only green plants can make their own food from sunlight. Green plants therefore, always occupy the 1st trophic level in a food chain. 

Answer is (B) Snake

Answer is (B) Snake

A) Both a & b are true

B) Pyramid of energy

Answer is (B) i, ii

A) Both a and b are true

i) If producers are more in number, then tertiary consumers are less in number, 

ii) If secondary consumers disappear the primary consumers increase in number and the tertiary consumers found no food to live. It leads to death.

i) In the year 1967. Because lake was not brought under cultivation.

ii) Excessive nutrient addition, especially from anthropogenic sources, led to explosive weed growth. Ex: Eichornia, pistia.

iii) 

1. In 1996, almost entire lake was brought under cultivation. 

2. Industries came along in ever growing intensity in the catchment area of the lake.

iv)

1. Consequently, the drains and rivulets carry substantial quantity of various types of pollutants into the lake. 

2. The major sources of pollution are agricultural runoff containing residues of several agrochemicals, fertilizers, fish tank discharges, industrial effluents containing chemical residues.

v)

1. The water of the lake turned alkaline in nature, turbid, nutrient rich, low in dissolved oxygen and high in biochemical oxygen demand. 

2. Water borne diseases like diarrhoea, typhoid, amoebiasis and others are said to be common among the local inhabitants who are unaware of the state of pollution in the lake water. 

3. Vector borne diseases were also increased.

vi) To avoid extreme cold weather conditions in Northern Asia and Eastern Europe birds migrate to Kolleru lake.

Kulhads are made of soil. Use of earthen kulhads is not an environmentally friendly decision because for making enough kulhads upper layer of fertile soil is used. Loss of fertile soil can make land barren and unproductive. The removal of the layer of soil makes field to lose its fertility making it unfit for agriculture purpose.

The two main components of our environment are the biotic or living components and abiotic or non-living components.

A food chain normally has three trophic levels. The primary producer, plants who will who will obtain nutrition from sunlight and prepare food for itself and for the second trophic level organism. The secondary consumers, herbivores that will eat plants, and at last will be the tertiary consumers called carnivores, the flesh eaters. They will feed on secondary consumers.

Wastes pollute our environment, air, soil and water, and cause harmful effects on all living organisms.

Phyto planktons 

\(\downarrow\)

Small aquatic animals larvae, shrimps, Insects 

\(\downarrow\)

Fish 

\(\downarrow\)

Bird

The answer is (a) Decrease in energy at higher trophic levels

• Available energy level at a particular trophic level is 10 times the energy level at next tropic level. 
• When we reach fourth trophic level; a minute portion of energy from producer is available.

Plastic bags are non-biodegradable wastes' they are not degraded, they begin to stink' emitting foul gases, spoil the beauty of places and contaminate soil, water, and air with toxins. Cloth bags are used instead of plastic bags because they are stronger, more durable and washable.

The answer is (d) (ii) and (iv)

• (Group i) has wood and leather which are biodegradable. 
• (Group iii) has grass which is biodegradable hence the answer is (d) (ii) and (iv)

A group of individuals belonging to the same species is Population.

(b) Grass, goat and human.

Different kinds of ecosy stem together constitute Biosphere.

When UV radiations from the sun reaches earth’s atmosphere which is heavily rich in oxygen. Then these UV rays split molecular oxygen (O₂) into free oxygen (O). Afterwards, this free oxygen reacts with molecular oxygen; it forms ozone (O₃). 

O₂ \(\overset{UV}\longrightarrow\) O + O

O + O₂ → O₃

This ozone now protects the earth from harmful UV radiations of sun, by allowing only some percent of rays to fall on the earth’s surface. Ozone acts as a filter of sun rays. These rays can cause skin cancer in human and can also affect other living organisms.

The ozone layer is reduced when man-made CFC molecules (comprised of chlorine, fluorine, and carbon) reach the stratosphere and are broken apart by UV energy from the sun.

These substances that lower the ozone layer do not directly destroy ozone. First they undergo photolysis, forming hydrogen chloride (HCl) or chlorine nitrate (ClONO₂), molecules that do not react with ozone directly, but slowly decompose, giving, among other things, a small number of chlorine atoms (Cl) and of chlorine monoxide (ClO) molecules that catalyze the destruction of ozone. 

The reactions involved in the processes of destruction are more than 100, but can be simplified in the following: 

Cl + O₃→ ClO + O₂ 

ClO + O → Cl + O₂ 

Net effect: O₃ + O → 2 O₂ 

The chlorine atom acts as a catalyst, ie it is not consumed in the reaction, so it destroys thousands of ozone molecules before disappearing.

Measures that can be taken are:

1. Limit private vehicle driving

This is because vehicular emissions eventually result in the release of smog. This in turn also damages the ozone layer causing it to deteriorate. You can choose to take the public transport or use a bicycle. Another great way to restrict the use of car is by opting for Car Pooling. If you do want to use a vehicle, then it is recommended to switch to an electric or hybrid vehicle.

2. Use eco-friendly household cleaning products 

Usage of Eco-friendly and natural cleaning products for household chores is a great way to prevent ozone depletion. This is because many of these cleaning agents contain toxic chemicals that interfere with the ozone layer. A lot of supermarkets and health stores sell cleaning products that are toxic-free and made out of natural ingredients.

3. Avoid using pesticides and prevent ozone depletion 

Pesticides may be an easy solution for getting rid of weed, but are harmful for the ozone layer. The best solution for this would be to try using natural remedies, rather than heading out for pesticides.

4. Buy air-conditioning and refrigeration equipment that do not use HCFCs as refrigerant.

Ozone is a simple chemical compound that contains only oxygen atoms, and its effects depend on where in the atmosphere it occurs. In the upper stratosphere, it forms a protective shield against solar ultraviolet radiation, but near the ground, it's a pollutant that can cause respiratory ailments in humans and animals. The creation and destruction of stratospheric ozone depend primarily on natural processes, but near the ground, industrial processes are mostly responsible for its creation. 

Hence ozone is the gas found at higher level of atmosphere (stratosphere). 

Chemical Composition 

An ozone molecule consists of three oxygen atoms (O₃), whereas the stable form of oxygen that normally exists in the atmosphere consists of only two. When certain chemical processes make an extra oxygen atom available, the highly reactive atom binds readily with an oxygen molecule. 

Then these UV rays split molecular oxygen (O₂) into free oxygen (O). Afterwards, this free oxygen reacts with molecular oxygen; it forms ozone (O₃). 

O₂ \(\overset{UV}\longrightarrow\) O + O

O + O₂ → O₃ (Ozone)

Damage to this layer is of great concern as this ozone protects the earth from harmful UV radiations of sun, by allowing only some percent of rays to fall on the earth’s surface. Ozone acts as a filter of sun rays. These rays can cause skin cancer in human and can also affect other living organisms.

10 J will be available to the secondary consumer to transfer to the tertiary consumer.

The smallest amount of energy transferred between organisms is shown by arrow number 4. Because as we go above in a food chain the amount of energy transferred is reduced by 10%. And the largest amount of energy loss to the ecosystem is in the form of heat. It is shown by arrow number 3. This is because producers(plants) take energy from sunlight and only 1% of it is used to prepare food rest other is lost is the form of heat.

Sun is the ultimate source of energy in an ecosystem. Energy always flows from sun to the producer through photosynthesis. From producers energy transfers to different consumers. It always flow from sun to producer and then to consumers.

I will ask the following questions to know more about flow of energy in an ecosystem. 

1. How does the energy flow in an ecosystem from one organism to other? 

2. Is the energy transformation from one level to other 100% efficient? 

3. What per cent of energy transfers from one level to other? 

4. What happens to the remaining energy? 

5. How does the ecosystem lose its energy during energy transformation? 

6. Which tropic level in an ecosystem has more energy and which has less? 

7. What is the ultimate source of energy in an ecosystem?

(i) Number of deer increases which will result in Iess amount of grass leading to soil erosion.

(ii) Food availab}e Ior lions would be less.  Amount of grassland will increase.

D) The population of tigers decreases and the population of grass increases.

If all the lions are removed, then there will be no predator control over the population of deer due to which its populations will greatly increase and deer will eat all grass. Over grazing will eliminate the grass and other green plants completely and turn the lush green forest into a desert area having no vegetation at all.

Removal of lions from the above food chain will increase the number of deer to such an extent that they will eat up the whole grass. The density of producer like grass will be very much reduced and this will turn the area into a desert.

(i) Fossil fuel - non-renewable.
(ii) (a) Travelling in public transport; arranging for car pools.
(b) Opting for CNG as a motor fuel instead of petrol and diesel.
(iii) Concern for environment, judicious use of non renewable sources of energy.

1. As we move from producers to different levels of consumers the energy available will decrease gradually. 

2. Only ten per cent of the energy present in one tropic level transfer to another tropic level. 

3. Biomass also decreases gradually as only 10 – 20% of the biomass is transferred from one tropic level to the next in a food chain. 

4. As there is less energy & less biomass available at top levels, number of organisms also less, generally. 

5. So, the number of organisms get decreased as we move from producer to different level of consumers.

1. b. Carnivores

2. c. Omnivores

3. d. All of the above

4. b. Lizard

5. a. Herbivores

(a) primary consumer to secondary consumer.
(b) producer to primary consumer.
(c) secondary consumer to tertiary consumer.