Class 7 Science Chapter 12 MCQ

Forests serve as green lungs as they produce oxygen for breathing and respiration and help in maintaining oxygen and carbon dioxide balance in the atmosphere.

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.

A tree has the strongest stem.

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

Thermocol is not prepared from the wood obtained from the forest. Paper, matchsticks and plywood are prepared from the wood.

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.

Honey, catechu (kattha) and gum are forest products but ginger is not a forest product.

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 are not responsible for creating flood conditions, as they protect from flood condition.

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.

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.

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 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.

The forest has a wide variety of animals. The type of animals also differ from forest to forest. The common animals which are found in forest in our country are monkey, jackal, elephants, tigers, lions, squirrel, porcupine, peacock, snakes, honey bees and other various small animals. The insects such as butterflies, honey bees and birds help in flowering plants of the forest in pollination not an Antelopes. An African animal with horns and long, thin legs that can run very fast. It looks like deer.

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

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].

Many tribal people of our country live in the forests. Forests are the lifeline for the forest-dwelling people. The cutting down of forests is driving out many populations but these are curse for them. Trees gives us oxygen, medicine, food, rain as well as shelter for human beings and animals.

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.