The atomic number of an element is determined by:(A) The number of electrons in an atom(B) The number of neutrons in one atom(C) The valency of the element(D) The number of protons in one atom

Describe briefly any five kinds of irrigation systems developed to supply water to agricultural lands?

• Surface Irrigation: This is the most common method where water flows over the soil surface and infiltrates into the soil. It includes furrow, basin, and flood irrigation techniques.
• Drip Irrigation: A highly efficient method that delivers water directly to the roots of plants through a network of tubing and emitters, minimizing evaporation and runoff.
• Sprinkler Irrigation: Involves using a system of pipes to distribute water through a series of overhead sprinklers, simulating rainfall over the crop area.
• Subsurface Irrigation: Similar to drip irrigation, but the water is delivered below the soil surface, providing moisture directly to the root zone and reducing evaporation.
• Center Pivot Irrigation: A mechanized system that rotates around a pivot point, allowing for the controlled application of water over large fields in a circular pattern.

Briefly explain the ecological pyramid which is always upright.

An oligotrophic lake is characterised by

• A. great changes in water level
• B. Long food chains
• C. Low nutrient and little life
• D. High nutrient levels and abundant flora and fauna

An allele is described as ‘dominant’ if it expresses itself when it occurs in

• A. Heterozygous condition
• B. Homozygous condition
• C. Both heterozygous condition and homozygous conditions
• D. Hemizygous condition

Which of the following is not an example of natural polymer?

• A. Wool
• B. Silk
• C. Leather
• D. Nylon