Model Test Paper 2

Rocks are those solid materials that make up the outer layer or crust of the Earth.

Ores are those rocks that contain metallic minerals only. Manganese ore and iron ore are so called as we derive metals from them.

Three hazards of mining are as follows:

1. Mine dust creates air pollution and its inhalation leads to respiratory diseases.
2. Mine tailings, the mud-like waste material released from mines, may cause water pollution as they are toxic in nature.
3. Heavy metal pollution by harmful minerals such as arsenic, lead and mercury can cause severe health hazards to human beings and marine creatures.

Three methods of conservation of minerals are as follows:

1. The principle of three Rs—Recycle, Reuse and Reduce—should be followed. It means reducing wastage of resources by recycling and reusing them.
2. Use renewable substitutes, wherever possible. For example, using hydroelectricity or solar power to reduce consumption of fossil fuels.
3. We need to use minerals judiciously so that we can meet our present needs and at the same time keep enough resources for the growth and development of our future generations. Also, aim for a development that minimises environmental problems. This is known as sustainable development.

The major seas and oceans which surrounds the continent of North America are as follows:

1. Arctic Ocean in the North
2. the Gulf of Mexico and the Caribbean Sea in the South
3. the Atlantic Ocean in the east
4. and Pacific Oceans in the west

The important deserts of North America are:

1. Great Basin Desert
2. Mojave Desert
3. Sonoran Desert
4. Chihuahuan Desert

A lumberjack leads an isolated life which is full of hardships.

1. They set out in autumn to live in temporary wooden houses, or shanties, with steep roofs. Sometimes, constructing a house becomes a problem due to permanent frost on the ground.
2. Therefore, in summer, the lumberjacks build many kilometres of rough track roads deep into the forest. This track leads to the lumber camps, which consist of a few buildings with a kitchen, a dining room and a bedroom.
3. The climate is extremely cold, especially in winter, making outdoor work very difficult.
4. They have to cut down large trees using heavy tools and machinery, which is physically exhausting.
5. In the past, lumberjacks returned home walking many kilometres after several months of stiff work in the forest.

In the earlier days, lumberjacks used to live in lumber camps, which consist of a few buildings with a kitchen, a dining room and a bedroom. Earlier, their houses used to be crudely built log cabins, but today, they are more comfortable. Most of the lumberjacks now live in settled communities.

The life of the Canadian lumberjacks is on the way to modernisation. Following the introduction of a wide range of modern scientific tools and new techniques of lumbering, the task of the - lumberjacks has become much easier than that of their predecessors. Many lumberjacks earn huge amount of money after working for several years in the log farms. They are called lumber barons. Some of the richest people in Canada today are the lumber barons. They enjoy a very high standard of living.

Two distinguishable features of a young fold mountain are as follows:

1. They are mountains that have been formed in the last 2 million years and occur in parallel ranges.
2. Steep slopes with sharp and high crests distinguish these mountains from old-fold ones.

Two notable features of the Eastern Highlands are as follows:

1. They are a part of the old land mass of Gondwanaland and are made up of very old rocks such as those found in the Deccan Plateau in India.
2. The old, hard rocks of the Eastern Highlands are rich sources of minerals such as iron ore and tin.

The Andes were formed in relatively recent period in the long history of the Earth. Rocks on the Earth's surface were compressed and folded owing to the forces acting in the interior of the Earth. This continues even today and makes this region prone to earthquakes and volcanic activities.

Today the area under the Amazon rainforest or Selvas is rapidly declining because of the following reasons:

1. Shifting cultivation along with reckless human activities such as ranching, mining, logging and urbanisation.
2. In the recent past, forest fires have become the biggest threat to the Amazon rainforest. Sometimes, the forest continues to burn for a long time, thus reducing vast reserves of oxygen.
3. Millions of trees in the Amazon have been lost to logging and fires in recent years.
4. In the name of development, mining and logging are active in the region while the forest is paying a very heavy price. The forest dwellers remain mere spectators to the vanishing habitat.