Vardaan Learning Institute

Ans: (c) Temperature
Abiotic means non-living. Temperature, light, soil are abiotic factors.

Ans: (a) Carnivores
1st: Producers, 2nd: Herbivores (Primary Consumers), 3rd: Carnivores (Secondary Consumers).

Ans: (b) Chlorofluorocarbons (CFCs)
CFCs release chlorine atoms which breakdown ozone into oxygen.

Ans: (a) Decrease in energy at higher trophic levels
According to 10% law, energy decreases at each step, leaving very little energy after 3-4 levels.

Ans: (c) Fruit-peels, cake and lime-juice
All items in this group can be broken down by decomposers.

Ans: (b) Convert organic material to inorganic forms
They break down complex organic matter into simple inorganic substances (nutrients) affecting recycling.

Ans: (b) Lindeman
Lindeman proposed the 10% law of energy transfer.

Ans: (b) Crop field
Crop fields are man-made and managed ecosystems. Pond, Lake, Forest are natural.

Ans: (b) Producers
Organisms (Plants) that make their own food (organic) from inorganic substances using light energy.

Ans: (b) Skin cancer
UV radiation damages DNA and causes skin cancer.

Ans: (a) Both A and R are true and R is the correct explanation of A.
Energy goes from Sun $\rightarrow$ Plants $\rightarrow$ Herbivores. It never goes back to the Sun or from Herbivores to Plants.

Ans: (b) Both A and R are true but R is not the correct explanation of A.
Ozone protects by absorbing UV rays. Formation (from UV action on O2) is a true fact but not the explanation of HOW it protects.

Ans: (a) Both A and R are true and R is the correct explanation of A.
Chemicals concentrate more at each higher level. Since humans are at the top, they have max concentration.

Ans: (a) Both A and R are true and R is the correct explanation of A.
Decomposition by microorganisms produces nutrient-rich manure (humus).

The phenomenon of progressive increase in the concentration of harmful non-biodegradable substances (like pesticides) at successive trophic levels.
Yes, max concentration is found at the top trophic level (e.g., humans) and min at the bottom (producers).

Ozone is $O_3$.
High energy UV radiations split oxygen molecule ($O_2$) into free oxygen atoms ($O$).
$O_2 \xrightarrow{UV} O + O$
These atoms combine with molecular oxygen to form ozone.
$O + O_2 \rightarrow O_3$.

Decomposers (bacteria/fungi) break down dead organic remains.
Consequences of absence: 1. Dead bodies would pile up. 2. Nutrients would not be returned to soil (cycle stops), affecting plant growth.

Example: Grass $\rightarrow$ Insect $\rightarrow$ Frog $\rightarrow$ Snake.
Limited steps because at each step, 90% energy is lost (10% law). After 3-4 steps, negligible energy remains for the next level.

Biodegradable: Substances broken down by biological processes (Bacteria/Saprophytes). e.g., Paper, Wood, Cotton.
Non-biodegradable: Substances NOT broken down by biological processes. They persist in environments for long. e.g., Plastic, DDT, Glass.

Energy captured by autotrophs does not revert back to the solar input. Energy which passes to the herbivores does not come back to autotrophs. As it moves progressively through various trophic levels, it is no longer available to the previous level.

(i) Problems: Persistence in environment, biological magnification, clogging drains, soil pollution, death of animals (eating plastic).
(ii) Methods: 1. Recycling (Plastics/Metals), 2. Composting (Biodegradable waste), 3. Incineration (Burning waste at high temp).

(i) Diagram: Sun $\rightarrow$ Producer $\rightarrow$ Primary Consumer $\rightarrow$ Secondary Consumer.
(ii) Plant (10,000 J) $\rightarrow$ Grasshopper ($10\%$ of 10,000 = 1000 J) $\rightarrow$ Frog ($10\%$ of 1000 = 100 J) $\rightarrow$ Snake ($10\%$ of 100 = 10 J) $\rightarrow$ Hawk ($10\%$ of 10 = 1 J).
Answer: 1 J.

(i) $O_3$.
(ii) Chlorofluorocarbons (CFCs).
(iii) 1. Reduce use of non-biodegradable materials (plastic bags).
2. Segregate waste into biodegradable and non-biodegradable bins for proper treatment.

(i) They are non-biodegradable and cannot be metabolized, so they get stored in body tissues.
(ii) Organisms at the top trophic level (Top Carnivores/Humans).
(iii) Because accumulation of toxic chemicals like DDT can cause serious health problems, cancer, and damage immune/reproductive systems.