Explanation

The Earth was formed about 4.5 billion years ago.

Additional information:

• Method Used: Radiometric dating
• Oldest Materials: Meteorites and ancient Earth rocks
• Scientific Consensus: Supported by geology and astronomy

Last verified on 16-01-2026

Explanation

• Histosols are soils rich in organic matter and usually peaty or boggy.
• Commonly found in cold, wet regions like Canada and Alaska.
• Formed in areas with poor drainage and slow decomposition.
• Important for carbon storage and wetland ecosystems.
• Often used for specialized agriculture or forestry.

Last verified on 06-02-2026

Explanation

• Tomato is rich in Vitamin C (ascorbic acid).
• Supports immune system and skin health.
• Also contains antioxidants like lycopene.
• Helps in collagen formation and wound healing.

Additional information:

• Orange – Vitamin C
• Carrot – Vitamin A
• Spinach – Vitamin K, iron
• Banana – Vitamin B6, potassium

Last verified on 06-02-2026

Explanation

• Taxonomy is the science of classifying and naming organisms.
  • Helps organize plants, animals, and microorganisms into groups.
  • Based on shared characteristics, genetics, and evolutionary relationships.
  • Developed initially by Carl Linnaeus in the 18th century.

Last verified on 06-02-2026

Explanation

• Citrus fruits (like oranges, lemons, limes) originated in the Indo-Chinese region of Southeast Asia.
• Includes parts of India, Myanmar, and Southern China.
• Cultivated for juice, flavor, and nutrition.
• Rich in vitamin C and antioxidants.
• Now widely grown in tropical and subtropical regions worldwide.

Last verified on 06-02-2026

Explanation

• Oceans cover roughly 71% of the Earth’s surface.
  • Land constitutes the remaining 29%, including continents and islands.
  
  
  Additional information:
  • Largest Ocean: Pacific Ocean (~63 million sq. miles)
  • Other Oceans: Atlantic, Indian, Southern, Arctic
  • Oceans store 97% of Earth’s water.

Last verified on 15-01-2026

Explanation

• American cotton (Gossypium hirsutum) is tetraploid, meaning it has four sets of chromosomes (2n = 4x = 52).
• Tetraploid cotton combines genes from two ancestral diploid species.
• Provides high fiber quality and yield.
• Commonly cultivated in USA, Pakistan, and India.
• Important for textile industry and hybrid seed production.

Last verified on 06-02-2026

Explanation

• Crossing over is the exchange of genetic material between non-sister chromatids of homologous chromosomes.
  • Occurs during prophase I of meiosis.
  • Increases genetic variation in gametes.
  • Ensures diverse traits in offspring.
  • Essential for evolution and natural selection.

Last verified on 06-02-2026

Explanation

• Crops grown in hilly or mountainous areas are often low in iodine.
• Due to soil erosion and leaching of minerals in high rainfall regions.
• Can lead to iodine deficiency in local populations.
• Iodine is essential for thyroid hormone production.
• Supplementation or iodized salt is commonly recommended.

Last verified on 06-02-2026

Explanation

• Population genetics studies the distribution of genes in populations over time.
• Based on Hardy-Weinberg law, which predicts allele and genotype frequencies under ideal conditions.
• Explains how mutation, selection, migration, and genetic drift affect populations.
• Helps in understanding evolution and breeding programs.

Last verified on 06-02-2026