Humus is partially decayed organic matter. It makes soil porous, thereby increasing its air and water holding capacity. It is rich in nutrients (e.g., minerals) that promote plant growth. Being black or dark brown in colour, humus absorbs heat to warm up the soil.
Humus is partially decayed organic matter. It makes soil porous, thereby increasing its air and water holding capacity. It is rich in nutrients (e.g., minerals) that promote plant growth. Being black or dark brown in colour, humus absorbs heat to warm up the soil.
The phenomenon of increase in the concentration of harmful non-biodegradable substances in the body of living organisms at each trophic level of the food chain is called bio magnification. Two heavy metals which are biomagnified are mercury and cadmium.
The phenomenon of increase in the concentration of harmful non-biodegradable substances in the body of living organisms at each trophic level of the food chain is called bio magnification. Two heavy metals which are biomagnified are mercury and cadmium.
Eutrophication is nutrient enrichment (i.e., addition of nitrates and phosphates) of water body that results in the growth of aquatic plants, especially algae causing colouration of water known as algal bloom. It leads to depletion of dissolved oxygen in water resulting in killing of aquatic organisRead more
Eutrophication is nutrient enrichment (i.e., addition of nitrates and phosphates) of water body that results in the growth of aquatic plants, especially algae causing colouration of water known as algal bloom. It leads to depletion of dissolved oxygen in water resulting in killing of aquatic organisms (e.g., fish).
These are substances which cannot be broken down by the activity of microorganisms. These substances go on concentrating at each trophic level of food chain, e.g., DDT and heavy metal (mercury, cadmium, etc.).
These are substances which cannot be broken down by the activity of microorganisms. These substances go on concentrating at each trophic level of food chain, e.g., DDT and heavy metal (mercury, cadmium, etc.).
Generally, tetraethyl lead is added to petrol to make it burn smoothly in motor vehicles. However, burning of petrol in automobiles releases toxic lead compounds through the exhaust pipes of automobiles. Continuous inhalation of these compounds causes anaemia, brain damage, convulsions and even deatRead more
Generally, tetraethyl lead is added to petrol to make it burn smoothly in motor vehicles. However, burning of petrol in automobiles releases toxic lead compounds through the exhaust pipes of automobiles. Continuous inhalation of these compounds causes anaemia, brain damage, convulsions and even death.
Name two measures which prevent the soil erosion.
(i) Intensive cropping and reforestation; (ii) Terrace farming.
(i) Intensive cropping and reforestation; (ii) Terrace farming.
See lessWhat is humus? What are its functions?
Humus is partially decayed organic matter. It makes soil porous, thereby increasing its air and water holding capacity. It is rich in nutrients (e.g., minerals) that promote plant growth. Being black or dark brown in colour, humus absorbs heat to warm up the soil.
Humus is partially decayed organic matter. It makes soil porous, thereby increasing its air and water holding capacity. It is rich in nutrients (e.g., minerals) that promote plant growth. Being black or dark brown in colour, humus absorbs heat to warm up the soil.
See lessWhat do you mean by biological weathering? Give two examples.
The whole process of weathering of rocks involving living organisms is called biological weathering, e.g., Lichens, mosses, herbs, shrubs and trees.
The whole process of weathering of rocks involving living organisms is called biological weathering, e.g., Lichens, mosses, herbs, shrubs and trees.
See lessWhat is biomagnification? Name two heavy metals which, when magnified resulted in diseases in humans.
The phenomenon of increase in the concentration of harmful non-biodegradable substances in the body of living organisms at each trophic level of the food chain is called bio magnification. Two heavy metals which are biomagnified are mercury and cadmium.
The phenomenon of increase in the concentration of harmful non-biodegradable substances in the body of living organisms at each trophic level of the food chain is called bio magnification. Two heavy metals which are biomagnified are mercury and cadmium.
See lessDefine eutrophication. What is ill effect of eutrophication?
Eutrophication is nutrient enrichment (i.e., addition of nitrates and phosphates) of water body that results in the growth of aquatic plants, especially algae causing colouration of water known as algal bloom. It leads to depletion of dissolved oxygen in water resulting in killing of aquatic organisRead more
Eutrophication is nutrient enrichment (i.e., addition of nitrates and phosphates) of water body that results in the growth of aquatic plants, especially algae causing colouration of water known as algal bloom. It leads to depletion of dissolved oxygen in water resulting in killing of aquatic organisms (e.g., fish).
See lessWhat are non-biodegradable substances?
These are substances which cannot be broken down by the activity of microorganisms. These substances go on concentrating at each trophic level of food chain, e.g., DDT and heavy metal (mercury, cadmium, etc.).
These are substances which cannot be broken down by the activity of microorganisms. These substances go on concentrating at each trophic level of food chain, e.g., DDT and heavy metal (mercury, cadmium, etc.).
See lessList main sources of water pollution.
(i) Sewage; (ii) Industrial wastes; (iii) Synthetic soaps and detergents; (iv) Fertilizers and pesticides; (v) Petroleum; (vi) Heat.
(i) Sewage; (ii) Industrial wastes; (iii) Synthetic soaps and detergents; (iv) Fertilizers and pesticides; (v) Petroleum; (vi) Heat.
See lessName two fresh water sources which provide fresh water for human use.
1. Ground water; 2. Surface water (ponds, lakes, streams, rivers, etc.).
1. Ground water; 2. Surface water (ponds, lakes, streams, rivers, etc.).
See lessWhy is lead compound added to petrol? What is its harm?
Generally, tetraethyl lead is added to petrol to make it burn smoothly in motor vehicles. However, burning of petrol in automobiles releases toxic lead compounds through the exhaust pipes of automobiles. Continuous inhalation of these compounds causes anaemia, brain damage, convulsions and even deatRead more
Generally, tetraethyl lead is added to petrol to make it burn smoothly in motor vehicles. However, burning of petrol in automobiles releases toxic lead compounds through the exhaust pipes of automobiles. Continuous inhalation of these compounds causes anaemia, brain damage, convulsions and even death.
See lessName two examples of green house gases which contribute maximum toward global warming.
Carbon dioxide and methane.
Carbon dioxide and methane.
See less