Decomposers are the microorganisms that convert the dead plants and animals into humus. Bacteria and mushroom are the two types of decomposers.
They help in the process of recycling of nutrients by decomposing various dead organisms such as plants and animals to form humus. Therefore, decomposers are helpful for the environment.

Forests are called the green lungs. This is because plants in forests release oxygen through the process of photosynthesis and help in providing oxygen to animals for respiration. They consume carbon dioxide released by the animals. In this way, plants help in maintaining a balance of oxygen and carbon dioxide in atmosphere.

There is no waste in a forest because microorganisms act on the wastes and convert them into humus. The humus ensures that the nutrients are returned back to the soil.

(i) Fruits
(ii) Vegetables
(iii) Medicines
(iv) Oxygen
(v) Cereals

There are various reasons for which we should be vigilant about matters related to forests:
(i) A decrease in forest area would lead to an increase in carbon dioxide in air. This will lead to an increase of earth's temperature.
(ii) Soil erosion would occur if there are no forests.
(iii) Floods would occur if there are no forests
(iv) Forests provide shelter and food to the living organisms.

A greater variety of plants and animals in the forests help it to regenerate and grow. Greater variety of plants means more food and habitat for the herbivores. An increase in herbivores means more food for carnivores.

Boars, bisons, jackals, porcupines, elephants, etc., live in the deeper areas of the forest.

Paheli observed that there is no noise pollution in a forest even though there are lots of heavy vehicles passing from the nearby highway. It is because trees present in the forest absorb the noise.

The variation in the type of plants and animals is found in different forests because of the climatic conditions of that particular area.

Grass ⟶ Insects ⟶ Frog ⟶ Eagle

No, due to different climatic conditions, there are variations in the types of trees and other plants. From forest to forest.

Since, all food chains are interlinked disturbance in one food chain will affect the other food chain in a forest.

The papers are made from wood pulp. We derive wood by cutting down trees. If we recycling existing quantity of paper in the market and will not let it decompose, we can stop cutting of forest trees for new raw materials required for paper making.It takes years to grow a tree and cutting a tree takes only few minutes. So, we should give a serious thought before cutting a single tree even and should encourage recycling of papers every where In our country and in the world.

(a) Sachin noticed the disturbance in the water cycle in his area like stream drying up. Pond water getting muddy, less availability of fuel wood, etc.
(b) Deforestation.
(c) Love for nature and environmental consciousness.

(a) The sequence of living organisms in which one organism eats another is called a food chain.
(b) \(\underset { (Procedur) }{ Grass } \longrightarrow \underset { (Herbivore) }{ Insect } \longrightarrow \underset { (Carnivore) }{ Frog } \longrightarrow \underset { (Large\quad carnivore) }{ Snake } \longrightarrow \underset { (Top\quad carnivore) }{ Eagle } \)
(c)Scientific attitude, Obligation to maintain the ecosystem of nature.