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Question (1)

QN0029873

A plant kept in sunlight with proper water showed healthy green leaves, while another plant kept in darkness with water developed yellow leaves. What is the most likely reason for this difference?

(A) Darkness increases mineral absorption
(B) Chlorophyll cannot function properly without sunlight
(C) Water destroys chlorophyll in dark
(D) Roots stop absorbing water in dark

Correct Answer: B

Explanation:

Sunlight is essential for photosynthesis and proper functioning of chlorophyll. Without sunlight, leaves become yellow and weak.

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Question (2)

QN0029874

In an experiment, a leaf was decolourised before adding iodine solution. Why was the leaf decolourised?

(A) To remove water from the leaf
(B) To soften the leaf
(C) To clearly observe the blue-black colour change
(D) To remove starch from the leaf

Correct Answer: C

Explanation:

Removing green chlorophyll helps us easily detect the blue-black colour indicating starch.

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Question (3)

QN0029875

A student kept a potted plant in darkness for 36 hours before performing a starch test. Why was this done?

(A) To increase starch formation
(B) To remove stored starch from leaves
(C) To increase chlorophyll content
(D) To dry the leaves completely

Correct Answer: B

Explanation:

Keeping the plant in darkness uses up previously stored starch, making the experiment accurate.

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Question (4)

QN0029876

Which combination is essential for photosynthesis to occur in leaves?

(A) Oxygen, minerals, sunlight
(B) Water, sunlight, chlorophyll, carbon dioxide
(C) Nitrogen, sunlight, oxygen
(D) Water, oxygen, minerals, starch

Correct Answer: B

Explanation:

Water, sunlight, chlorophyll, and carbon dioxide are all necessary for photosynthesis.

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Question (5)

QN0029877

A leaf with green and non-green patches was tested with iodine after exposure to sunlight. Only green regions turned blue-black. What does this prove?

(A) Only green patches contain water
(B) Chlorophyll is necessary for starch formation
(C) Green patches absorb oxygen
(D) Non-green patches contain extra starch

Correct Answer: B

Explanation:

Blue-black colour indicates starch, which formed only where chlorophyll was present.

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Question (6)

QN0029878

In a setup, half of a leaf was inserted into a bottle containing caustic soda solution. After iodine testing, only the outer part of the leaf turned blue-black. Which conclusion is correct?

(A) Oxygen is essential for starch formation
(B) Water is absent inside the bottle
(C) Carbon dioxide is necessary for photosynthesis
(D) Chlorophyll was absent outside the bottle

Correct Answer: C

Explanation:

Caustic soda absorbs carbon dioxide, so the inner part could not perform photosynthesis.

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Question (7)

QN0029879

During photosynthesis, plants mainly release which gas into the atmosphere?

(A) Nitrogen
(B) Carbon dioxide
(C) Oxygen
(D) Hydrogen

Correct Answer: C

Explanation:

Oxygen is released as a by-product during photosynthesis.

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Question (8)

QN0029880

A water plant kept under sunlight released bubbles in water, but no bubbles appeared in darkness. These bubbles mainly contained—

(A) Nitrogen
(B) Oxygen
(C) Carbon dioxide
(D) Water vapour

Correct Answer: B

Explanation:

Photosynthesis occurs in sunlight and releases oxygen gas.

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Question (9)

QN0029881

Which statement correctly explains why leaves are called “food factories” of plants?

(A) Leaves store only minerals
(B) Leaves absorb food from soil
(C) Leaves prepare food by photosynthesis
(D) Leaves transport food to roots only

Correct Answer: C

Explanation:

Food synthesis mainly occurs in leaves due to chlorophyll and sunlight.

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Question (10)

QN0029882

If stomata of leaves are blocked, which process will be directly affected first?

(A) Seed formation
(B) Gas exchange
(C) Root growth
(D) Water absorption

Correct Answer: B

Explanation:

Stomata are tiny pores responsible for exchange of gases.

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Question (1)

A plant kept in sunlight with proper water showed healthy green leaves, while another plant kept in darkness with water developed yellow leaves. What is the most likely reason for this difference?

Explanation:

Link:

Question (2)

In an experiment, a leaf was decolourised before adding iodine solution. Why was the leaf decolourised?

Explanation:

Link:

Question (3)

A student kept a potted plant in darkness for 36 hours before performing a starch test. Why was this done?

Explanation:

Link:

Question (4)

Which combination is essential for photosynthesis to occur in leaves?

Explanation:

Link:

Question (5)

A leaf with green and non-green patches was tested with iodine after exposure to sunlight. Only green regions turned blue-black. What does this prove?

Explanation:

Link:

Question (6)

In a setup, half of a leaf was inserted into a bottle containing caustic soda solution. After iodine testing, only the outer part of the leaf turned blue-black. Which conclusion is correct?

Explanation:

Link:

Question (7)

During photosynthesis, plants mainly release which gas into the atmosphere?

Explanation:

Link:

Question (8)

A water plant kept under sunlight released bubbles in water, but no bubbles appeared in darkness. These bubbles mainly contained—

Explanation:

Link:

Question (9)

Which statement correctly explains why leaves are called “food factories” of plants?

Explanation:

Link:

Question (10)

If stomata of leaves are blocked, which process will be directly affected first?

Explanation:

Link:

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