In a cell of bacteria and blue green algae (=cyanobacteria), a well organised nucleus is absent (1.e., there is no nuclear envelope and nucleolus) and membrane-bound organelles are lacking. Such cells are called prokaryotic cells.
In a cell of bacteria and blue green algae (=cyanobacteria), a well organised nucleus is absent (1.e., there is no nuclear envelope and nucleolus) and membrane-bound organelles are lacking. Such cells are called prokaryotic cells.
(a) Dams are referred to as multi-purpose projects where the many uses of the impounded water are integrated with one another. Dams are now built not just for irrigation but for electricity generation, water supply for domestic and industrial uses, flood control and recreation. (b) The objectives ofRead more
(a) Dams are referred to as multi-purpose projects where the many uses of the impounded water are integrated with one another. Dams are now built not just for irrigation but for electricity generation, water supply for domestic and industrial uses, flood control and recreation.
(b) The objectives of the projects were as mentioned below:
(i) It would integrate development of agriculture and the village economy with rapid industrialisation and growth of the urban economy. It was thought that they would lead the nation to development and progress, overcoming the handicap of its colonial past.
(ii) These projects generate hydro-electricity. For example, the Bhakra-Nangal project water is being used for hydel power production
(iii) The projects are useful for irrigation as is the case of Bhakra project.
(iv) Flood control: These projects help in the control of floods. For example the Hirakud project in the Mahanadi basin integrates conservation of water with flood control.
(v) The other objectives are navigation, fish breeding, water supply for domestic and industrial uses and to encourage tourism.
The following factors are responsible for the poor condition of India,s rivers – (a) Smaller rivers: (l) The growing - domestic, municipal, industrial and agricultural demand for water from rivers has affected the quality of water. The volume of rivers has been reduced as more and more water is beinRead more
The following factors are responsible for the poor condition of India,s rivers –
(a) Smaller rivers: (l) The growing – domestic, municipal, industrial and agricultural demand for water from rivers has affected the quality of water. The volume of rivers has been reduced as more and more water is being drained out of them.
(ll) A heavy load of untreated sewage and industrial effluents are emptied into the rivers. This also affects the self-cleansing capacity of the rivers leading to rising pollution of their water. As a result of above factors, the smaller rivers have all turned into toxic streams.
(b) Big rivers: These rivers have been affected by the following factors –
(i) Population growth
(ii) Agricultural modernisation
(iii) Urbanisation
(iv) Industrialisation: Industries are heavy users of water and also require hydroelectric power to run them. For example in Delhi, a large amount of domestic and industrial waste falls in the Yamuna river that leads to water pollution. Thus even the big rivers like the Ganga and yamuna are far from being pure and efforts are being made to clean the rivers.
(a) A dam is a barrier across flowing water that obstructs, directs’ or retards that flow, often creating a reservoir, lake or impoundment. It has a section called a spillway or weir over which or through which water flows intermittently or continuously. (b) (i) Based on structure and the materialsRead more
(a) A dam is a barrier across flowing water that obstructs, directs’ or retards that flow, often creating a reservoir, lake or impoundment. It has a section called a spillway or weir over which or through which water flows intermittently or continuously.
(b) (i) Based on structure and the materials used., dams are classified as timber dam, embankment dams or masonry dams.
(ii) According to height, dams can be categorised as large dams and major dams or alternatively as low dams, medium height dams and high dams.
The water was conserved in ancient India by constructing sophisticated hydraulic structures like dams built of stone rubble, reservoirs or lakes, embankments and canals for irrigation. Some of the hydraulic structures in ancient India were as follows: (l) In the first century B.C., Sringaverapura neRead more
The water was conserved in ancient India by constructing sophisticated hydraulic structures like dams built of stone rubble, reservoirs or lakes, embankments and canals for irrigation. Some of the hydraulic structures in ancient India were as follows:
(l) In the first century B.C., Sringaverapura near Allahabad, had sophisticated water harvesting system channelling the flood water of the river Ganga.
(ii) During the reign of Chandragupta Maurya, dams, lakes and irrigation systems were extensively built.
(iii) Irrigation works have been found in many places viz., Kalinga(Orissa), Nagarjunakonda (Andhra Pradesh), Bennur (Karnataka) and Kolhapur (Maharashtra).
(iv) In the 11th century, Bhopal Lake was built. It was one of the largest artificial lakes of its time.
(v) In the 14th century, the tank in Hauz Khas, Delhi was constructed. by ltutmish. It supplied water to Siri Fort area.
It is necessary to conserve and manage our water resources due to the following reasons: (l) To safeguard ourselves from health hazards: Polluted water is not good for health. It may cause various kinds of water borne diseases. Water polluted by domestic and industrial wastes, chemicals, pesticidesRead more
It is necessary to conserve and manage our water resources due to the following reasons:
(l) To safeguard ourselves from health hazards: Polluted water is not good for health. It may cause various kinds of water borne diseases. Water polluted by domestic and industrial wastes, chemicals, pesticides and fertilisers makes it hazardous for human use.
(ii) To ensure food security: Sufficient water is required for growing crops to meet the food requirement in the country. Shortage of water may lead to condition of drought and failure of crops.
(iii) To prevent degradation of our natural ecosystems: Over exploitation and mismanagement of water resources will impoverish this resource and cause ecological crisis that may have profound impact on our lives. We cannot imagine a life without water. Thus it is very necessary to conserve and manage our water without which there can be no life on earth.
Some facts and figures about water are given below: (i) 96.5 per cent of the total volume of world's water exists as oceans. (ii) 2.5 per cent of the total volume of world's water exists as freshwater. 70 per cent of the freshwater occurs as ice-sheets and glaciers in Antarctica, Greenland and the mRead more
Some facts and figures about water are given below:
(i) 96.5 per cent of the total volume of world’s water exists as oceans.
(ii) 2.5 per cent of the total volume of world’s water exists as freshwater. 70 per cent of the freshwater occurs as ice-sheets and glaciers in Antarctica, Greenland and the mountainous regions of the world. Only less than 30 per cent is stored as groundwater in the world’s aquifers.
(iii) The total renewable water resources of India are estimated at 1,897 sq km per annum.
(iv) India receives nearly 4 per cent of the global precipitation and ranks 133 in the world in terms of water availability per person per annum.
(v) It is predicted that there will be absolute water scarcity in large parts of India by 2025.
What is prokaryotic cell?
In a cell of bacteria and blue green algae (=cyanobacteria), a well organised nucleus is absent (1.e., there is no nuclear envelope and nucleolus) and membrane-bound organelles are lacking. Such cells are called prokaryotic cells.
In a cell of bacteria and blue green algae (=cyanobacteria), a well organised nucleus is absent (1.e., there is no nuclear envelope and nucleolus) and membrane-bound organelles are lacking. Such cells are called prokaryotic cells.
See lessWhat is cell?
Cell is the structural and functional unit of life.
Cell is the structural and functional unit of life.
See lessWhat is a multi-purpose river valley project? Give any four objectives of the multi-purpose river valley project.
(a) Dams are referred to as multi-purpose projects where the many uses of the impounded water are integrated with one another. Dams are now built not just for irrigation but for electricity generation, water supply for domestic and industrial uses, flood control and recreation. (b) The objectives ofRead more
(a) Dams are referred to as multi-purpose projects where the many uses of the impounded water are integrated with one another. Dams are now built not just for irrigation but for electricity generation, water supply for domestic and industrial uses, flood control and recreation.
See less(b) The objectives of the projects were as mentioned below:
(i) It would integrate development of agriculture and the village economy with rapid industrialisation and growth of the urban economy. It was thought that they would lead the nation to development and progress, overcoming the handicap of its colonial past.
(ii) These projects generate hydro-electricity. For example, the Bhakra-Nangal project water is being used for hydel power production
(iii) The projects are useful for irrigation as is the case of Bhakra project.
(iv) Flood control: These projects help in the control of floods. For example the Hirakud project in the Mahanadi basin integrates conservation of water with flood control.
(v) The other objectives are navigation, fish breeding, water supply for domestic and industrial uses and to encourage tourism.
Describe the factors that are responsible for the poor condition of India’s rivers – both smaller and big rivers.
The following factors are responsible for the poor condition of India,s rivers – (a) Smaller rivers: (l) The growing - domestic, municipal, industrial and agricultural demand for water from rivers has affected the quality of water. The volume of rivers has been reduced as more and more water is beinRead more
The following factors are responsible for the poor condition of India,s rivers –
See less(a) Smaller rivers: (l) The growing – domestic, municipal, industrial and agricultural demand for water from rivers has affected the quality of water. The volume of rivers has been reduced as more and more water is being drained out of them.
(ll) A heavy load of untreated sewage and industrial effluents are emptied into the rivers. This also affects the self-cleansing capacity of the rivers leading to rising pollution of their water. As a result of above factors, the smaller rivers have all turned into toxic streams.
(b) Big rivers: These rivers have been affected by the following factors –
(i) Population growth
(ii) Agricultural modernisation
(iii) Urbanisation
(iv) Industrialisation: Industries are heavy users of water and also require hydroelectric power to run them. For example in Delhi, a large amount of domestic and industrial waste falls in the Yamuna river that leads to water pollution. Thus even the big rivers like the Ganga and yamuna are far from being pure and efforts are being made to clean the rivers.
What is a dam? How are they classified?
(a) A dam is a barrier across flowing water that obstructs, directs’ or retards that flow, often creating a reservoir, lake or impoundment. It has a section called a spillway or weir over which or through which water flows intermittently or continuously. (b) (i) Based on structure and the materialsRead more
(a) A dam is a barrier across flowing water that obstructs, directs’ or retards that flow, often creating a reservoir, lake or impoundment. It has a section called a spillway or weir over which or through which water flows intermittently or continuously.
See less(b) (i) Based on structure and the materials used., dams are classified as timber dam, embankment dams or masonry dams.
(ii) According to height, dams can be categorised as large dams and major dams or alternatively as low dams, medium height dams and high dams.
How was the water conserved in ancient India? Give some examples in support of your answer.
The water was conserved in ancient India by constructing sophisticated hydraulic structures like dams built of stone rubble, reservoirs or lakes, embankments and canals for irrigation. Some of the hydraulic structures in ancient India were as follows: (l) In the first century B.C., Sringaverapura neRead more
The water was conserved in ancient India by constructing sophisticated hydraulic structures like dams built of stone rubble, reservoirs or lakes, embankments and canals for irrigation. Some of the hydraulic structures in ancient India were as follows:
See less(l) In the first century B.C., Sringaverapura near Allahabad, had sophisticated water harvesting system channelling the flood water of the river Ganga.
(ii) During the reign of Chandragupta Maurya, dams, lakes and irrigation systems were extensively built.
(iii) Irrigation works have been found in many places viz., Kalinga(Orissa), Nagarjunakonda (Andhra Pradesh), Bennur (Karnataka) and Kolhapur (Maharashtra).
(iv) In the 11th century, Bhopal Lake was built. It was one of the largest artificial lakes of its time.
(v) In the 14th century, the tank in Hauz Khas, Delhi was constructed. by ltutmish. It supplied water to Siri Fort area.
Why is it important to conserve and manage our water resources? Give any three reasons:
It is necessary to conserve and manage our water resources due to the following reasons: (l) To safeguard ourselves from health hazards: Polluted water is not good for health. It may cause various kinds of water borne diseases. Water polluted by domestic and industrial wastes, chemicals, pesticidesRead more
It is necessary to conserve and manage our water resources due to the following reasons:
See less(l) To safeguard ourselves from health hazards: Polluted water is not good for health. It may cause various kinds of water borne diseases. Water polluted by domestic and industrial wastes, chemicals, pesticides and fertilisers makes it hazardous for human use.
(ii) To ensure food security: Sufficient water is required for growing crops to meet the food requirement in the country. Shortage of water may lead to condition of drought and failure of crops.
(iii) To prevent degradation of our natural ecosystems: Over exploitation and mismanagement of water resources will impoverish this resource and cause ecological crisis that may have profound impact on our lives. We cannot imagine a life without water. Thus it is very necessary to conserve and manage our water without which there can be no life on earth.
Give some facts and figures about water in the world.
Some facts and figures about water are given below: (i) 96.5 per cent of the total volume of world's water exists as oceans. (ii) 2.5 per cent of the total volume of world's water exists as freshwater. 70 per cent of the freshwater occurs as ice-sheets and glaciers in Antarctica, Greenland and the mRead more
Some facts and figures about water are given below:
See less(i) 96.5 per cent of the total volume of world’s water exists as oceans.
(ii) 2.5 per cent of the total volume of world’s water exists as freshwater. 70 per cent of the freshwater occurs as ice-sheets and glaciers in Antarctica, Greenland and the mountainous regions of the world. Only less than 30 per cent is stored as groundwater in the world’s aquifers.
(iii) The total renewable water resources of India are estimated at 1,897 sq km per annum.
(iv) India receives nearly 4 per cent of the global precipitation and ranks 133 in the world in terms of water availability per person per annum.
(v) It is predicted that there will be absolute water scarcity in large parts of India by 2025.