CBSE Questions for Class 10 Biology Our Environment Quiz 7 - MCQExams.com

• The ozone layer or ozone shield is a region of Earth's stratosphere that absorbs most of the Sun's ultraviolet (UV) radiation. 
• It contains high concentrations of ozone (O$$_3$$) in relation to other parts of the atmosphere.

• Natural resource management refers to the management of natural resources such as land, water, soil, plants, and animals, with a particular focus on how management affects the quality of life for both present and future generations (stewardship)
• Hence proper management of natural resources ensures equitable distribution of natural resources and sustainable development.
• So, the correct answer is 'Both A and B'.

$$\textbf{Correct option: }$$ D

$$\textbf{Solution: }$$ 

$$\textbf{Option (A) }$$

$$\bullet$$The organisms feeding on the producer plants are known as herbivores. 

$$\textbf{Option (B) }$$

$$\bullet$$Plants are the producers of the planet as they are organism making their own food from inorganic substances. 

$$\textbf{Option (C) }$$

$$\bullet$$The primary carnivore is the organism that is completely dependent on the herbivore for its food consumption. 

$$\bullet$$These organisms are also known as the first level of a carnivore. 

$$\textbf{Option (D) }$$

$$\bullet$$The top predators are present on the peak trophic level of the ecosystem. 

$$\bullet$$The hazardous pesticide enters the trophic level and accumulates in the higher concentration after reaching the higher trophic level. 

$$\bullet$$This process is also known as Biomagnification. 

Hence, the correct option is (d).

• The feeding positions in a food chain or web are called trophic levels. 
• All food chains and webs have at least two or three trophic levels. 
• There are a maximum of four trophic levels. 
• Many consumers feed at more than one trophic level. 
• Generally, there are no more than four trophic levels because energy and biomass decrease from lower to higher levels.
  

• An ecosystem is a community of living organisms in conjunction with the non-living components of their environment, interacting as a system. 
• The fundamental source of energy in almost all ecosystems is radiant energy from the sun. 
• The autotrophs process the light energy and use the energy stored within the simple carbohydrates to produce the more complex organic compounds. 
• The flow of energy through the ecosystem drives the movement of nutrients within the ecosystem. 
• Decomposers play a key role in many of these cycles, returning nutrients to the soil, water, or air, where they can be used again by the biotic constituents of the ecosystem.

Among the given options bones will take the longest to get degraded. Bones are composed of proteins (mainly collagen), inorganic minerals (calcium, hydroxyapatite) and organic compounds. The unique structure of collagen protein (one of the most resistant proteins to degradation) gives strength to bones. In addition to this, inorganic ions such as calcium further strengthen the bones.

1. Microorganisms can degrade material derived from living matter. Eg- Paper
2. Bones are also derived from living matter, but the composition consists of a large amount of minerals.
3. Metal gets decomposed to its mineral form by the climatic conditions and takes few years.
4. Plastic is the least biodegradable material.

• An ecosystem is a structural and functional unit of ecology where living organisms interact with one another and their environment. 

• The components of environment include abiotic factors such as air, water, soil and biotic factors such as plants, humans, animals, microorganisms.

• Eggshell leather belts and rice grains are obtained naturally from living organisms and are made of biodegradable components.
• Plastic mugs are synthesized by humans in factors by making artificial polymers using chemicals that ultimately become non-biodegradable. It remains as it is for thousands of years in the same condition.