Explanation

• Sugar beet can develop a rotten smell when it undergoes microbial breakdown.
• This smell is caused by fermentation, where microorganisms convert sugars into alcohols, acids, and gases.

Additional information:

• Fermentation can spoil sugar beet if not processed quickly after harvest.
• Microorganisms like yeast and bacteria are responsible for this smell.

Last verified on 22-01-2026

Explanation

• Exhaustive crops are crops that remove large amounts of nutrients from the soil.
• Continuous cultivation of these crops can deplete soil fertility.
• Examples include nutrient-demanding cereal crops like maize, wheat, and rice.

Additional information:

• Maize, wheat, and rice remove large amounts of nitrogen, phosphorus, and potassium from the soil.

Last verified on 22-02-2026

Explanation

• Potato cultivation requires planting healthy seed tubers at the recommended seed rate for optimum yield.
• Recommended seed rate is 800–1200 kg per hectare.

Additional information:

• Seed tubers should be disease-free and healthy.
• Planting is done at 25–30 cm spacing between tubers for best results.

Last verified on 20-01-2026

Explanation

• The cell cycle is the sequence of stages a cell goes through to grow and divide.
• DNA synthesis (replication) occurs during the S Phase (Synthesis Phase).

Additional information:

1. G₁ Phase – cell growth before DNA replication
2. G₂ Phase – preparation for cell division after DNA replication
3. M Phase – actual mitosis/cell division

Last verified on 22-01-2026

Explanation

• Soil has different layers called horizons, each with specific properties.
• The plough pan is a hard, compact layer formed just below the depth reached by ploughing.
• It restricts root growth and water movement.

Last verified on 22-01-2026

Explanation

• Soil is home to a wide variety of living organisms that maintain soil fertility.
• Nematodes make up 80–90% of the living animals in soil.

Additional information:

• Nematodes are microscopic roundworms found in almost all soils.
• They help control pests and recycle nutrients for plants.

Last verified on 22-01-2026

Explanation

• Plants absorb light for photosynthesis mainly using chlorophyll pigments.
• The effective range of light absorbed is the visible spectrum that drives photosynthesis.
• Light outside this range is less effective for producing energy in plants.

Last verified on 22-01-2026

Explanation

• Chlorophyll is a compound that is called a Chelate.
• Photosynthesis depends on the presence of chlorophyll for the absorption of light.

Additional information:

There are about six closely related chlorophylls:

1. chlorophyll a
2. chlorophyll b
3. chlorophyll c
4. chlorophyll d
5. chlorophyll e
6. chlorophyll f

Last verified on 22-01-2026

Explanation

• A sales tax is a tax imposed by the government on a wide range of goods and services.
• It is collected at the point of sale from consumers.

Additional information:

• Sales tax is usually a percentage of the sale price, e.g., 17% in Pakistan.

Last verified on 22-01-2026

Explanation

• Honeybees have a unique sex-determination system called haplodiploidy.
• Queen and worker bees develop from fertilized eggs, making them diploid.

Additional information:

• Drones (male bees) develop from unfertilized eggs and are haploid.
• This system helps maintain colony structure and division of labor.

Last verified on 22-01-2026