List any four disadvantages of using fossil fuels for the production of energy.
The four disadvantages of using fossil fuels for the production of energy are:
i. It releses high concentration of posinous gases like oxides of sulphur and nitrogen which may cause air pollution and acid rain.
ii. It results in the increase of concentration of Carbon dioxide in the enviroment and hence reults in global warming.
iii. When burnt in less oxygen large amount of toxic gas Carbon monoxide is released which may have adverse effect on the organisms.
iv. They are non-renewable resources of energy, their overuse may lead to depletion of these resources.
State the meaning of inherited traits and acquired traits. Which of the two is not passed on to the next generation? Explain with the help of an example.
Inherited traits are those traits which can be passed from one generation to the next generation. These involve changes in the DNA.
Acquired traits - An acquired trait is a physical characteristic of an organism that is not passed down to offspring genetically. It is not coded in the organism's DNA and is a product of the environment's influence on the organism. These traits are acquired during the lifetime.
The acquired traits are not passed to the next generation. For example, if a person has increased the muscle strength and size by exercising regularly, then he/she cannot pass the same to their offspring.
What is sustainable management? Why is reuse considered better in comparison to recycle ?
Sustainable Management: It is a pattern of management that promises the use of natural resources in such a way that they meet the human needs in the present as well as in the future.
Advantage of Reuse over Recycling
Recycling requires a large amount of energy and money. Reuse, on the other hand, simply involves using things, again and again, preserves the embodied energy originally used in manufacturing an item. Reuse also creates less air and water pollution than recycling. Hence, reuse is preferred over recycling.
List three problems which arise due to the construction of big dams. Suggest a solution for these problems.
The construction of big dams poses the following problems:
(i) Social problems as the construction displace a large number of peasants and tribals without adequate compensation or rehabilitation.
(ii) They create economic problems as they use up huge amounts of public money without the generation of proportionate benefits.
(iii) Environmental problems because they contribute enormously to deforestation and the loss of biological diversity.
Energy flow in a food chain is unidirectional. Justify this statement. Explain how the pesticides enter a food chain and subsequently get into our body.
The flow of energy in the ecosystem is said to be unidirectional because only 10 percent of the energy is available in the next trophic level. Very less energy is left in the higher trophic levels. Most of the energy is lost as heat and cannot be reused by plants in photosynthesis. Therefore, the energy flow is unidirectional.
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