Class 7 Science Chapter 9 MCQ

Here, all the statements are correct. Hence, your answer will be option [D].

Weathering is the breaking down of huge pieces of rocks into smaller pieces by the action of natural forces such as water, glaciers, wind and roots of plants.

Soil is one of the most important natural resources. Soil supports for growth of plants and trees by holding their roots firmly and by supplying them with water and nutrients. Hence, soil is used to grow all types of plants not only for cotton plants.

The microorganisms present in the soil having plenty of water and nutrients are present in the habitat of forest.

Weathering of rocks is a very, very slow process. The process by which huge rocks are broken down into small particles by the action of sun’s heat, wind, rain and flowing river water etc., is called weathering. It takes thousands of years weather huge rocks or break down huge rocks into fine particles fit to make soil.

Here, all the statements are correct. Hence, your answer will be option [D].

Soil conservation measures mainly aim at protecting top soil, which is rich in humus and nutrients making it fertile to grow plants.

Here, all the situations are correct told by Boojho where Paheli can see the soil profile. Hence, your answer will be option [D].

Here, all the statements are correct. Hence, your answer will be option [D].

The largest size rock particles present in the soil are called gravel. Gravel is a kind of tiny stones. The amount of gravel present in a good top-soil is very small. The soil is mainly made up of different sized rock particles and humus. On the basis of their sizes, the rock particles present in soil can be divided into four groups: Clay, Silt, Sand and Gravel.

The smallest rock particles present in the soil form clay. The largest size rock particles present in the soil are called gravel. Gravel is a kind of tiny stones. The amount of gravel present in a good top-soil is very small.

Here, all the statements are correct. Hence, your answer will be option [D].

The soil with a low percolation rate of water would be the most suitable for growing paddy or rice crop.

Here, all the statements are correct. Hence, your answer will be option [D].

Here, all the statements are correct. Hence, your answer will be option [D].

The process by which huge rocks are broken down into small particles by the action of sun’s heat, wind, rain and flowing water, etc., is called Weathering. It is called weathering because the rocks are worn away to form small particles by long exposure to these elements of weather. Although weathering of rocks is a very slow process. It takes thousands of years to weather huge rocks or break down huge rocks into fine particles to make soil.

Here, all the statements are correct. Hence, your answer will be option [D].

Here, all the statements are correct. Hence, your answer will be option [D].

Deserts are made up of sand, thus when the rain water falls on land, it percolates immediately downwards in the spaces between sand particles. So, the streams of water in desert region are not visible even during rainy season.

Here, all the statements are correct. Hence, your answer will be option [D].

A material which gets decomposed through natural processes, such as action by bacteria, is called biodegradable. Such as card board, paper, leaves, wood, jute bag etc. A material which is not easily decomposed by natural processes is termed as non-biodegradable. Such as plastic, synthetic materials etc.

Remember, it is not a good practice to remove grass and small plants growing in an open, unused field because the plants cover the soil surface. Their roots bind the soil particles, holding and adhering them in place.

Here, all the statements are correct. Hence, your answer will be option [D].

Water percolating into the soil collects above the bedrock. This natural level of groundwater is called the water table.

Option A is correct with reference to soil while weathering is a slow process of soil formation and loamy soil consists of sand, clay and silt along with humus.