NCERT Class 9 Science — Chapter 3: Improvement in food resources

mcqeasy

Which one of the following is classified as a micronutrient required for plant growth?

Official previous-year question

Verified 1 Aug 2026.

Options

ACalcium
BPhosphorus
CBoron
DPotassium

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Solution

Correct Option

The correct option is

Boron

Explanation

Essential elements for plant growth are classified into two categories based on quantitative requirements: Macronutrients (required in large amounts, generally >10 mmole kg^-1 of dry matter) and Micronutrients (required in trace amounts, generally <10 mmole kg^-1 of dry matter).

Option Analysis

Potassium (K): It is a macronutrient essential for enzyme activation, stomatal movement, and osmoregulation.
Boron (B): It is a micronutrient required for uptake and utilization of calcium, membrane functioning, pollen germination, cell elongation, cell differentiation, and carbohydrate translocation.
Phosphorus (P): It is a macronutrient vital for energy transfer (ATP), nucleic acid synthesis, and root development.
Calcium (Ca): It is a macronutrient crucial for cell wall structure (middle lamella) and membrane stability.

Key Takeaway

Micronutrients required by plants include Iron (Fe), Manganese (Mn), Copper (Cu), Molybdenum (Mo), Zinc (Zn), Boron (B), Chlorine (Cl), and Nickel (Ni).

Your note

More from Chapter 3: Improvement in food resources

Consider the following statements regarding Manure: 1. It depletes the soil of organic matter. 2. In sandy soils, it increases the water holding capacity. 3. In clayey soils, organic matter helps in drainage. Which of the statements given above is/are correct?

medium

In the context of sustainable agriculture, what does the term 'Green Manure' refer to?

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Consider the following statements regarding weeds: 1. Xanthium and Parthenium are examples of beneficial crops. 2. Weeds compete with crop plants for food, space, and light. 3. Weeds are beneficial as they enhance nutrient absorption by crop plants. Which of the statements given above is/are correct?

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In the context of insect pests attacking plants, which of the following modes of attack are observed? 1. Cutting the root, stem, and leaf. 2. They provide nutrients to the plant by sucking cell sap. 3. Boring into stems and fruits. Select the correct answer using the code given below:

easy

Which one of the following agricultural practices is primarily used as a preventive measure for weed control?

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Correct Option

The correct option is

Boron

Explanation

Option Analysis

Potassium (K): It is a macronutrient essential for enzyme activation, stomatal movement, and osmoregulation.
Boron (B): It is a micronutrient required for uptake and utilization of calcium, membrane functioning, pollen germination, cell elongation, cell differentiation, and carbohydrate translocation.
Phosphorus (P): It is a macronutrient vital for energy transfer (ATP), nucleic acid synthesis, and root development.
Calcium (Ca): It is a macronutrient crucial for cell wall structure (middle lamella) and membrane stability.

Key Takeaway

Micronutrients required by plants include Iron (Fe), Manganese (Mn), Copper (Cu), Molybdenum (Mo), Zinc (Zn), Boron (B), Chlorine (Cl), and Nickel (Ni).