Consider the following statements about algae: 1. They are generally formed by the growth of organisms in stagnant water. 2. They appear green because they lack chlorophyll. 3. They are autotrophs and can prepare their own food. Which of the statements given above is/are correct?

The correct option is (c) 1 and 3 only Explanation Algae are chlorophyll-bearing, simple, thalloid, autotrophic, and largely aquatic (both fresh water and marine) organisms. They are capable of performing photosynthesis, which defines their mode of nutrition and pigmentation. Statement-wise Analysis - Statement 1 is Correct: Algae are commonly observed as slimy, green patches in stagnant water bodies or on wet surfaces. Their growth is often accelerated in nutrient-rich stagnant water, leading to phenomena such as algal blooms. - Statement 2 is Incorrect: Algae appear green specifically because they contain chlorophyll. Chlorophyll is the green pigment essential for photosynthesis. If they lacked chlorophyll, they would not appear green nor be able to perform photosynthesis efficiently. - Statement 3 is Correct: Algae are autotrophs. Due to the presence of chlorophyll, they capture sunlight to synthesize their own food through the process of photosynthesis, similar to higher plants. Key Takeaway: Algae are photosynthetic autotrophs that contain chlorophyll, which gives them their characteristic green color and enables them to synthesize their own food.

Consider the following statements about algae:… - NCERT Class 7 Science MCQ

NCERT Class 7 Science — Chapter 1: Nutrition in plants

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Consider the following statements about algae:

They are generally formed by the growth of organisms in stagnant water.
They appear green because they lack chlorophyll.
They are autotrophs and can prepare their own food.

Which of the statements given above is/are correct?

NCERT textbook question

From NCERT Science - class 7 · Page 4

Options

A1 and 2 only
B2 only
C1 and 3 only
D1, 2 and 3

Did you get this right?

Solution

The correct option is (c) 1 and 3 only

Explanation

Algae are chlorophyll-bearing, simple, thalloid, autotrophic, and largely aquatic (both fresh water and marine) organisms. They are capable of performing photosynthesis, which defines their mode of nutrition and pigmentation.

Statement-wise Analysis

Statement 1 is Correct: Algae are commonly observed as slimy, green patches in stagnant water bodies or on wet surfaces. Their growth is often accelerated in nutrient-rich stagnant water, leading to phenomena such as algal blooms.
Statement 2 is Incorrect: Algae appear green specifically because they contain chlorophyll. Chlorophyll is the green pigment essential for photosynthesis. If they lacked chlorophyll, they would not appear green nor be able to perform photosynthesis efficiently.
Statement 3 is Correct: Algae are autotrophs. Due to the presence of chlorophyll, they capture sunlight to synthesize their own food through the process of photosynthesis, similar to higher plants.

Key Takeaway: Algae are photosynthetic autotrophs that contain chlorophyll, which gives them their characteristic green color and enables them to synthesize their own food.

Your note

More from Chapter 1: Nutrition in plants

Consider the following statements regarding the relationship between legumes and Rhizobium: 1. It is an example of a symbiotic relationship. 2. The bacteria provide food and shelter to the plant. 3. The plant provides nitrogen to the bacteria. Which of the statements given above is/are correct?

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With reference to saprotrophic nutrition, consider the following statements: 1. It is a mode of nutrition where organisms take in nutrients from dead and decaying matter. 2. Fungi ingest dead matter directly without secreting digestive juices. 3. All fungi are harmful and cause spoilage of food and diseases. Which of the statements given above is/are correct?

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Consider the following statements about the transport system in plants: 1. Roots absorb water and minerals from the soil. 2. The transport vessels are restricted to the roots and do not reach the stem. 3. The vessels form a continuous network reaching the leaves. Which of the statements given above is/are correct?

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Which one of the following crops is a legume capable of symbiotic nitrogen fixation via Rhizobium?

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Consider the following statements about the digestive process in saprotrophs: 1. They digest food externally before ingestion. 2. They secrete digestive juices inside their bodies. 3. They absorb nutrients in solution form. Which of the statements given above is/are correct?

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