Explanation

• Hydrophytes are plants adapted to grow in water-rich environments such as ponds, lakes, and marshes.
• Examples: Water lily, Lotus, Hydrilla, and Rice (partially submerged).

Additional information:

• Plants that demand low water are called Xerophytes.

Last verified on 01-02-2026

Explanation

• Agriculture in Pakistan faces multiple challenges including water scarcity, outdated farming techniques, and small land holdings.
• These issues limit crop yield, productivity, and farmers’ income.

Additional information:

• Government programs like Irrigation Modernization and Farmer Training aim to address these problems.
• Use of high-yield varieties and mechanization can improve productivity.

Last verified on 30-01-2026

Explanation

• Palmitic acid (C16:0) is the most common saturated fatty acid in oils of crops like soybean, sunflower, and cottonseed.
• Saturated fatty acids contribute to stability and shelf life of oils.

Last verified on 01-02-2026

Explanation

• Starch is the primary storage carbohydrate in seeds of most plants.
• Provides energy for germination and early seedling growth.
• Examples: Wheat, rice, maize, and potato seeds contain high starch content.

Last verified on 01-02-2026

Explanation

• Phosphorus (P) is most available to plants in slightly acidic to neutral soils (pH 6–7.5).
• At low pH (4–5), phosphorus reacts with iron and aluminum, forming insoluble compounds.
• At high pH (8–9), it reacts with calcium, also becoming unavailable.

Last verified on 01-02-2026

Explanation

• Deela (Echinochloa colona / Echinochloa crus-galli) is a common weed in rice fields.
• Competes with rice for nutrients, water, and sunlight, reducing yield.
• Controlled through manual weeding, herbicides, or proper water management.

Last verified on 01-02-2026

Explanation

• Cotton (Gossypium spp.) is a C3 plant, meaning it uses the C3 (Calvin cycle) pathway for photosynthesis.
• In C3 plants, CO₂ is fixed directly into a 3-carbon compound (3‑phosphoglycerate).
• Examples of other C3 crops: wheat, rice, soybean, and potato.

Last verified on 01-02-2026

Explanation

• A wind vane (also called a weather vane) shows the direction from which the wind is blowing.
  • Usually installed on rooftops or meteorological stations.
  • Works with a rotating pointer that aligns with the wind direction.

Last verified on 01-02-2026

Explanation

• Restorative crops improve soil fertility by adding nutrients, especially nitrogen.
• Soybean, being a legume, fixes atmospheric nitrogen through Rhizobium bacteria in root nodules.
• Helps reduce the need for chemical nitrogen fertilizers in subsequent crops.

Last verified on 01-02-2026

Explanation

• Under submerged soil conditions, oxygen is low, so nitrate (NO₃⁻) quickly converts to gases (denitrification).
• Ammonium (NH₄⁺) is more stable in anaerobic (waterlogged) soils like paddy fields.
• Common ammonium fertilizers for rice: Urea, Ammonium sulfate, Ammonium chloride.

Last verified on 01-02-2026