Bihar Board - Class 12 Biology- Chapter 16: Environmental Issues Long Answer Question

1. What are the contributions of Ahmed Khan in Bangalore and Ramesh Chandra Dagar 1 in Sonipat?

Ans: Integrated organic farming is a zero-waste, cyclical process in which waste products from one operation are recycled into nutrients for those other processes. This provides for the most efficient use of resources and boosts productivity levels. This is exactly what Ramesh Chandra Dagar, a farmer in Sonipat, Haryana, is doing. Natural gas is used to meet the farm's energy needs. Beekeeping, water harvesting, dairy management, composting, and agriculture are all part of a chain of activities that support each other and allow for a very cost-effective and long-term endeavor. Because cattle excreta (dung) has been used as manure, there is no need to put artificial fertilizers on crops. Crop waste is turned into compost that can be utilized as a natural fertilizer or used to produce natural gas to meet the farm's energy demands. Dagar founded the Haryana Kisan WelfareClub, which now has 5000 members and is dedicated to disseminating information and assisting farmers in the practice of integrated organic farming.

2. Write notes on electronic wastes. Write about the various sources of e-wastes and issues associated with its disposal.

A. Solid wastes can be recyclable, biodegradable, non-biodegradable and can be categorized as municipal wastes – the sewage, hospital and nursing wastes, industrial wastes and electronic wastes. Mobiles, irreparable computers, and other such electronic goods are known as e-waste or electronic wastes. Some of their sources are:

• Many developing countries like India, China import irreparable electronic goods for their precious metals like nickel, gold, copper.

• E-wastes should be disposed of in landfills or incinerated

• Manual extraction of metals from e-wastes takes place in developing countries. Hence working with them can expose one to toxic substances present in it, leading to skin diseases

• Recycling is the only solution for e-waste treatment.3

3. Explain organic farming. In a developing nation like India, discuss its benefits as a viable practice.

A. In an eco-friendly and pollution-free environment, organic farming mainly aims at sustainable production. Cultivation on land happens through techniques such as green manure, crop rotation, composting and biological pesticides along with beneficial microbes instead of pesticides and chemical fertilizers. Few of its benefits are:

• Regulates diseases and pests without causing harm to the environment

• Maintains long-term soil fertility

• Assures that water remains safe and clean.

• To make it economic, use resources which already exists with the farmer

• Produces high-quality crops and nutritious food.

4. What are the causes and severe effects of soil salinity and waterlogging in the green revolution?

A. Soil salinity and waterlogging are caused by huge irrigation without suitable drainage of water. The constant presence of water trails salt to the soil surface, which accumulates as a thin crust on the surface of the land or begins to collect at the plant roots. Severe effects:

• High salt content exploits the growth of crop plants

• Cells of the roots get damaged with saline water saturation

• Plants tend to die

• The yield of crops is affected

• Farmers procure financial loss

5. Define multipurpose trees. Write the botanical and local names of any two multipurpose trees along with their uses.

A. Upon plantation, trees that fulfill a number of purposes are called multipurpose trees. These purposes can be providing shade, wood, fruit, food, soil improvement, etc. They serve a wide variety of services and functions for human needs. Azardicta, Indica – Neem, is well-known for its medicinal benefits. Its leaves, wood, fruit and the oil extracted from wood is mostly used in ayurvedic medicines.

Due to chemical azadirachtin, its wood is pest resistant. Coconut palm is another important tree, with the botanical name – Cocos Nucifera belongs to the family – Palmae and provides a variety of functions such as wood, oil, food fiber, etc and has medicinal, fiber and commercial importance. Another multipurpose tree is the Morinaoleifera and Gliricidia septum which is utilized for fences in Central America. It provides firewood fodder and fixes atmospheric nitrogen. It is commonly used for shade and animal forage and its leaves are edible.

6. Write three basic characteristics of a modern landfill site. What are the reasons they are used?

Ans. Following are the characteristics:

• Compaction and integument of the waste to prevent it from being blown by the wind

• Procedures to contain leachates such as lining clay or plastic liners

• To extract gas to use in the generation of power, landfills gas extraction systems are installed.

The following are the reasons why their use must be promoted:

• Through recycling and recovery of waste, they trigger the waste prevention

• A uniform cost for the disposal of waste  is created which subsequently will prevent the essential transport of waste.

• They help in bringing down negative effects on the environment and risk to human health that emerges from the landfilling of wastes.

7. Explain the working of the electrostatic precipitator.

Ans. They can eliminate 99% particulate matter that is found in the exhaust from a particular thermal power plant through these mechanisms:

• It contains electrode wires which are constantly maintained at a several thousand volts, which provides a corona releasing electrons.

• The electrons hence released are attached to dust particles offering them with a net negative charge

• The plates that collect, are grounded and draws through attraction the dust particles that are charged.

• The velocity of air is maintained low between the plates to facilitate falling of dust.