Class 7 Science Chapter 12 MCQ

As Boojho was entering the forest his class teacher told him not to make noise in the forest because it could disturb both birds and animals.

As leaves, trees, other plants and animals die, they all fall on the forest floor. The animal wastes also fall on the forest floor and collect there. On the forest floor, there are a large number of the decomposers such as bacteria and fungi. The decomposers break down dead leaves, branches and trees, dead animals and animal wastes to form humans which contain the nutrients or mineral salts. Humus mixes up with the soil in the forest and the nutrients present in it are used for the growth of plants.

Porcupine is the smallest forest animal among the following given in the options.

Forests provide us many useful products such as fire-wood, timber, honey, fruits, sealing wax or lac, catechu, natural rubber, medicinal plants, fodder and wood for making paper. Plywood is normally made from wood. And kerosene is petroleum products which we get from crude oil. Hence, your answer will be option [D].

A tree has the strongest stem.

The forest is an ecosystem consisting of living things such as plants, animals and decomposers and non-living things such as soil, water and air. In the forest ecosystem, there is an interaction between living things and non-living environment. When plants and animals die, then the decomposers organisms decompose their dead bodies into nutrients, water and carbon dioxide. Nutrients and water are returned to the soil, and carbon dioxide is returned to the air. These nutrients, water and carbon dioxide are then re-used for the growth of new plants in the forest. And this process goes on and on like an un-ending chain. Thus, we can say that the various components of a forest are interdependent on one another.

Porcupine is not the name of a tree rather it is an animal. Teak, Sal and Kachnar are names of trees.

From the above given options, semal and hornbill are the names of a tree and an animal, respectively.

he first step in every food chain is the plants. They are also referred as “Autotrophs”. The second step in a food chain is always a herbivore. The third step in a food chain is always a carnivore.

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

The branchy part of a tree above the stem is known as the “Crown” of the tree. The crown includes the top part of a tree which has all the branches and leaves of the tree.

Forests help in maintain water cycle in nature and hence bring sufficient rain. Forests prevent soil erosion and floods and hence help in the conservation of soil. Forests also maintain the balance between carbon di oxide and oxygen in the atmosphere. Destruction of forests can change the earth’s climate.

Those animals which eat dead animals’ area called scavengers. Scavengers eat up the dead bodies of animals and a help in keeping forest environment clean. Vultures, crows, jackals, hyena, some insects and beetles are the example of scavengers. Without scavengers’ dead body of the forest animals could not be got rid of quickly. But they are not decomposers.

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

Scavengers are not referred as decomposers. Scavengers are a kind of cleansing agent of the environment. Without scavengers’ dead body of the forest animals could not be got rid of quickly. But they are not decomposers. Because, they do not break down dead animals into simpler substances which can be reused by the plants.

When plants and animals die, then the decomposers organisms decompose their dead bodies into nutrients, water and carbon dioxide. Decomposers are commonly known as “saprotrophs”. Where nutrients and water are returned to the soil, and carbon dioxide is returned to the air. These nutrients, water and carbon dioxide are then re-used for the growth of new plants in the forest. And this process goes on and on like an un-ending chain.

The branchy part of a tree above the stem is known as the “crown” of the tree. The crowns of tall trees form a green cover over the forest land. The major functions of the crown of a tree are to absorb sun’s light energy, carry out photosynthesis, release oxygen and carry out the process of respiration and transpiration. All these functions are performed by the leaves of the crown.

We know that excessive cutting down of forest trees should not be allowed by the Government (any countries) to conserve forest. Trees should be planted in the forest in place of cut down trees to conserve forest. Paper products such as old newspaper, magazine books and notebooks etc., should be recycle to conserve forest. We get jute and cotton bags from plants. And plastic we made in laboratory through chemical substances. Though recycling of paper bags will help in the conservation of forest.

Amount of CO2 in air will increase. Forests help in maintain water cycle in nature and hence bring sufficient rain. Forests prevent soil erosion and floods and hence help in the conservation of soil. Forests also maintain the balance between carbon di oxide and oxygen in the atmosphere. Destruction of forests can change the earth’s climate.

In a forest, trees form the uppermost layer followed by shrubs and the herbs form the lowest layer of vegetation

No body has planted any trees in the natural forests. The natural forests contain trees and plants which have grown on their own.

Destruction of forests would not prevent flooding of rivers, loss of life and property. Destruction of forests can change the earth’s climate. There would be no life without forest.

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

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

Green plants and trees of the forest supply oxygen for breathing and respiration, so forests are known as green lungs.