CBSE Class 10 Biology Natural Resources Notes for 2025–2026 Board Exams

Mastering CBSE Class 10 Biology concepts in natural resource management is crucial for scoring top marks in your 2025–2026 board examinations. These comprehensive CBSE Class 10 Biology Natural Resources Notes cover the core principles of sustainable resource management, conservation strategies, stakeholder roles, and ecological balance aligned strictly with the latest NCERT syllabus.

Key Concepts: Management of Natural Resources

Natural resources are substances, organisms, and energy reserves found in nature that humans utilize for survival, industrial manufacturing, and socio-economic development. In CBSE Biology, natural resources are broadly classified into two categories based on abundance and replenishability:

• Inexhaustible / Renewable Resources: Resources that replenish naturally through physical, biogeochemical, or solar cycles and are not easily depleted by human consumption when managed sustainably (e.g., solar radiation, wind energy, tidal energy, and biomass).
• Exhaustible / Non-Renewable Resources: Resources with finite natural deposits that require millions of geological years to form and cannot be replaced once consumed (e.g., fossil fuels such as coal, crude petroleum, and mineral ores).

1. The 5 R's Principle for Environmental Conservation

To preserve biological ecosystems, reduce carbon footprints, and maintain ecological equilibrium, NCERT highlights the 5 R's framework:

• Refuse: Actively reject environmentally harmful products and unnecessary packaging, such as single-use plastic bags, disposable cutlery, and non-biodegradable items.
• Reduce: Minimize the consumption of natural resources by optimizing efficiency—switching off electrical appliances when idle, repairing leaking plumbing, and preventing food wastage.
• Reuse: Use items repeatedly across their usable life cycle rather than discarding them after a single use. Reusing glass jars, envelopes, and plastic containers consumes zero processing energy compared to industrial recycling.
• Repurpose: Adapt a discarded item for a new practical utility when it can no longer fulfill its primary function (e.g., using cracked ceramic mugs as seedling planters).
• Recycle: Segregate recyclable solid waste (paper, plastics, glass, metals) and send it to industrial processing plants to manufacture new materials instead of dumping them into municipal landfills.

2. Sustainable Management of Forests and Wildlife

Forests are quintessential biodiversity hotspots. The biological health of a forest is evaluated not merely by tree density, but by the diversity of endemic plant, animal, fungal, and microbial species living within the ecosystem.

Sustainable forest management requires balancing conservation goals with the demands of four primary stakeholders:

1. Local People & Tribals: Indigenous communities residing inside or adjacent to forest reserves who depend sustainably on minor forest produce (fodder, firewood, timber for housing, bamboo, medicinal herbs, and fruits) for their subsistence.
2. Forest Department: Government agencies holding administrative authority over public forest lands. Historically, colonial and early post-independence forestry promoted monoculture plantations (teak, pine, eucalyptus), which destroyed local biodiversity and deprived local populations of diverse forest resources.
3. Industrialists: Commercial manufacturers who exploit forests as raw material sources (for paper pulp, matchsticks, timber, sports goods, and resin). Industrialists typically lack long-term local conservation incentives and tend to move to new reserves after depleting an area.
4. Wildlife and Nature Enthusiasts: Conservation biologists, environmental NGOs, and citizens dedicated to preserving wilderness and endangered wildlife in their pristine state without commercial dependence.

3. Community Participation and Historic Conservation Movements

Democratic, community-driven resource governance has consistently outperformed centralized exclusion models in wildlife and forest conservation:

• Amrita Devi Bishnoi National Award: Honors the sacrifice of Amrita Devi Bishnoi and 363 members of the Bishnoi community who laid down their lives in 1731 to protect native Khejri trees (Prosopis cineraria) from royal felling in Khejarli, Rajasthan. The Government of India instituted this award for exemplary wildlife protection.
• The Chipko Movement (1970s): Initiated in Reni village, Garhwal (Uttarakhand), where local women embraced trees to physically prevent commercial loggers from clear-cutting their native hillside forests, successfully forcing the government to ban commercial logging in sensitive catchment areas.
• Arabari Forest Revival (West Bengal, 1972): Visionary forest officer A.K. Banerjee engaged local villagers in regenerating 1,272 hectares of severely degraded Sal (Shorea robusta) forest. By providing wage employment and granting local communities 25% of the final timber harvest along with fuel wood collection rights, a desolate tract was transformed into a lush forest ecosystem valued at over >12.5 crore rupees.

4. Water Management: Dams vs. Traditional Harvesting Systems

Water security is fundamental to agriculture and public health. Large multipurpose river valley projects (e.g., Tehri Dam on the Bhagirathi river, Bhakra Nangal Dam on the Sutlej, and the Sardar Sarovar Dam on the Narmada) generate hydroelectric power and provide regulated canal irrigation (such as the Indira Gandhi Canal in Rajasthan). However, major dams face severe criticisms:

• Social Problems: Forced displacement of large agrarian and tribal populations without adequate land-for-land compensation or socio-economic rehabilitation.
• Economic Problems: Enormous expenditure of public funds without delivering equitable benefits to downstream farmers.
• Environmental Problems: Submergence of vast tracts of virgin forest, irreparable loss of biological biodiversity, soil salinization in canal command areas, and disruption of downstream riverine ecology.

In contrast, indigenous rainwater harvesting systems are decentralized, community-managed structures that replenish local groundwater aquifers without causing environmental degradation:

5. Coal and Petroleum Management

Fossil fuels such as coal and petroleum formed millions of years ago through the anaerobic decay of prehistoric plant and animal biomass under intense subterranean heat and pressure. When combusted, these hydrocarbons release carbon dioxide (CO₂), water vapor, oxides of nitrogen (NOₓ), and sulfur dioxide (SO₂). Incomplete combustion releases hazardous carbon monoxide (CO) and unburnt carbon particulates (soot). Rising atmospheric CO₂ concentrations intensify the greenhouse effect, accelerating global climate change and oceanic acidification. Sustainable energy policies require minimizing fossil fuel dependence, expanding public transit infrastructure, and transitioning toward renewable solar and wind technologies.

Important CBSE Questions with Answers

The following questions represent high-yield core concepts frequently evaluated in the CBSE Class 10 Biology board examinations:

Question 1

Q: Define nutrition. Name the mode of nutrition in Amoeba.

Answer:
Nutrition is the physiological process by which an organism ingests, digests, absorbs, transports, and assimilates food nutrients to synthesize cellular components and release metabolic energy required for life processes.
The mode of nutrition in Amoeba is holozoic nutrition (specifically phagocytosis). Amoeba uses temporary, finger-like extensions of its cell surface called pseudopodia to engulf food particles, forming a intracellular food vacuole where complex nutrients are broken down enzymatically into simple diffusible substances.

Question 2

Q: What is the role of stomata in plants?

Answer:
Stomata are microscopic specialized pores located primarily on the lower and upper epidermis of leaves, flanked by regulatory guard cells. Their critical roles include:

1. Gaseous Exchange: Facilitating the diffusion of carbon dioxide (CO₂) into the leaf for photosynthetic carbon fixation, and the release of metabolic byproduct oxygen (O₂), as well as oxygen uptake for cellular respiration.
2. Transpiration: Regulating the evaporation of water vapor from aerial plant tissues. This process creates a continuous hydrostatic suction gradient (transpirational pull) that drives the upward ascent of water and dissolved minerals through xylem vessels, while simultaneously providing evaporative cooling to leaf tissues.

Question 3

Q: What is the function of the enzyme pepsin in the human digestive system?

Answer:
Pepsin is an active endopeptidase enzyme secreted in its inactive precursor form (pepsinogen) by the chief (peptic) cells of the gastric glands in the stomach mucosa. In the presence of hydrochloric acid (HCl), which provides an optimal acidic environment (pH 1.5–2.5), pepsinogen is converted into active pepsin. Pepsin digests complex dietary proteins by hydrolyzing internal peptide bonds, converting them into smaller polypeptides, peptones, and proteoses:
$$\text{Proteins} \xrightarrow{\text{Pepsin (Acidic pH 1.5–2.5)}} \text{Peptones} + \text{Proteoses}$$

Question 4

Q: What is the function of the cerebrum?

Answer:
The cerebrum constitutes the largest and most complex part of the human forebrain. Its main functions include:

• Cognitive Processing: Serving as the main site for conscious thought, reasoning, analytical problem-solving, memory storage, speech formulation, and learning.
• Sensory Integration: Housing specialized sensory areas that receive and interpret nerve impulses from sense organs (visual cortex for sight, auditory area for hearing, olfactory area for smell, gustatory area for taste, and somatic sensory areas for touch, temperature, and pain).
• Voluntary Motor Control: Motor areas generate and transmit nerve impulses to skeletal muscles to initiate and coordinate voluntary motor movements.
• Consciousness and Emotional Behavior: Governing consciousness, personality, emotional responses, and voluntary decision-making.

Question 5

Q: Name the gland that produces both digestive enzymes and insulin.

Answer:
The gland is the Pancreas. It is a composite heterocrine (dual-function) gland comprising both exocrine and endocrine functional units:

• Exocrine Function: Pancreatic acinar tissue secretes alkaline pancreatic juice containing key digestive enzymes, including pancreatic amylase (carbohydrate digestion), trypsin and chymotrypsin (protein digestion), and pancreatic lipase (emulsified fat digestion) into the duodenum via the pancreatic duct.
• Endocrine Function: The specialized Islets of Langerhans secrete regulatory hormones directly into the bloodstream—primarily insulin (from $\beta$-cells to lower blood glucose levels by promoting cellular glucose uptake and glycogenesis) and glucagon (from $\alpha$-cells to raise blood glucose levels via glycogenolysis).

Question 6

Q: What is the role of auxin in plant growth? Give two examples.

Answer:
Auxin (principally Indole-3-acetic acid / IAA) is a master plant growth phytohormone synthesized predominantly at actively dividing shoot and root apical meristems. It promotes cellular elongation, cell division, vascular differentiation, and directional tropic movements.
Two key examples of auxin action:

1. Phototropism: When a growing shoot receives unidirectional light from one side, auxin molecules migrate and concentrate on the shaded side of the stem. The higher auxin concentration stimulates increased cell elongation on the shaded side relative to the illuminated side, creating differential growth that bends the shoot toward the light source.
2. Apical Dominance: High concentrations of auxin produced at the terminal apical bud suppress the growth of lateral (axillary) buds, encouraging vertical growth of the main stem until the apex is pruned.

Question 7

Q: What happens to the pH of the mouth after eating? Why does tooth decay occur?

Answer:
After consuming meals, particularly those rich in sugars and fermentable carbohydrates, oral bacteria (such as Streptococcus mutans) ferment residual food particles adhered to teeth surfaces, producing organic acids. Consequently, the pH of the oral cavity drops below 5.5.
Mechanism of tooth decay: Tooth enamel is composed of calcium hydroxyapatite (a crystalline salt of calcium phosphate), which is the hardest biological substance in the human body. Although chemically insoluble in water, tooth enamel undergoes acid-mediated demineralization (corrosion) whenever the oral pH falls below 5.5. Repeated acidic exposure demineralizes the enamel, allowing bacterial penetration into the softer underlying dentin and pulp cavity, resulting in dental caries (cavities). Regular brushing with alkaline toothpastes neutralizes bacterial acids and prevents enamel erosion.

Question 8

Q: How is the amount of urine produced regulated in the human body?

Answer:
The volume of urine formed by kidney nephrons is regulated through osmoregulatory feedback loops based on total body hydration status and the concentration of dissolved nitrogenous wastes (urea, uric acid):

1. Hormonal Regulation via ADH (Antidiuretic Hormone / Vasopressin): Osmoreceptors in the hypothalamus detect hemoconcentration (reduced blood volume or elevated solute concentration due to dehydration). The posterior pituitary responds by secreting ADH into the circulation. ADH increases the permeability of the distal convoluted tubules (DCT) and collecting ducts to water by inserting aquaporin channels, leading to increased facultative water reabsorption back into peritubular capillaries. This produces a low volume of concentrated urine, conserving vital body water.
2. Response to Hydration Excess: When an individual consumes excess water, osmoreceptors inhibit ADH secretion. Tubular water reabsorption drops significantly, causing large volumes of dilute urine to be excreted.

How to Prepare for This Topic for Board Exam 10

To maximize your score in the board exam 10 Biology papers for the 2025–2026 academic session, apply these targeted revision practices:

• Precise Biological Terminology: CBSE evaluation criteria reward accurate terminology (e.g., phagocytosis, facultative reabsorption, calcium hydroxyapatite, apical dominance). Avoid generic or conversational phrasing in descriptive answers.
• State-Specific Water Harvesting Matching: Memorize the regional names of water harvesting systems (such as Khadins, Kulhs, Ahars, and Surangams) as they are frequently tested in objective 1-mark MCQs and assertion-reason questions.
• Flowcharts for Physiological Pathways: Draw clear schematic flow diagrams for multi-step processes like osmoregulatory feedback, phototropism mechanisms, and digestive enzyme pathways to secure full step marks.
• Solve Prior Year Questions (PYQs): Practice standard 2-mark, 3-mark, and 5-mark NCERT exemplar and CBSE past-year questions under timed conditions to refine answer presentation.

Where to Practice More

Consistent, exam-oriented practice is the most dependable way to achieve a perfect 100 in Class 10 Science. Generate customized CBSE question papers, attempt chapter-wise diagnostic tests, and access step-by-step marking scheme solutions at Theorify QPTool (qptool.theorify.in).