Explanation

• Nitrobacter bacteria convert nitrite (NO₂⁻) into nitrate (NO₃⁻) in the soil.
• This is the second step of the nitrification process, which is important for plant nutrition.
• Nitrite is toxic to plants, but nitrate is easily absorbed as a nutrient.

Last verified on 22-01-2026

Explanation

• The seed coat protects the embryo inside the seed.
• The outermost layer of the seed coat is called Testa.
• It acts as a barrier against mechanical damage, pathogens, and water loss.

Additional information:

• Testa may have hair, wax, or spines in some seeds.
• Plays a role in seed dormancy and protection.

Last verified on 25-01-2026

Explanation

• Plants can respond to various stimuli like light, gravity, and touch.
• The response of plants to touch is called thigmotropism.
• It is commonly seen in climbing plants and vines, which coil around supports.

Last verified on 23-01-2026

Explanation

• Oomycetes are fungus-like organisms, often called water molds.
• Although they resemble true fungi, their cell wall composition is different.
• In oomycetes, the cell wall is mainly composed of cellulose.

Additional information:

• True fungi have chitin in their cell walls, while oomycetes have cellulose.
• A common example of oomycetes is Phytophthora, which causes plant diseases.

Last verified on 23-01-2026

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

• The study of humans has multiple branches focusing on biology, culture, and history.
• Anthropology specifically studies the evolution and biological development of humans.
• It examines humans as part of the animal kingdom and their physical, social, and cultural traits.

Last verified on 22-01-2026

Explanation

• The endosperm is the main storage tissue in maize seeds.
• It containing nutrients like starch, proteins, and oils.
• It support the growth of the embryo during germination.

Last verified on 22-01-2026

Explanation

• Plants need gas exchange for photosynthesis and respiration.
• Exchange of CO₂, O₂, and water vapor occurs through stomata on leaves.
• Stomata are tiny pores controlled by guard cells.

Additional information:

• Helps maintain internal water balance and gas diffusion.
• Essential for growth, energy production, and transpiration.

Last verified on 22-01-2026

Explanation

• The first process in a petroleum refinery is Distillation.
• It is also known as Fractional Distillation.
• This process separates crude oil into various fractions or types of hydrocarbons, based on their boiling points and molecular weights.

Additional information:

The processes in a petroleum refinery:

1. Cracking
2. Reforming
3. Isomerization
4. Hydrotreating
5. Hydrocracking
6. Catalytic Cracking
7. Alkylation

Last verified on 22-01-2026

Explanation