Biology · The Living World · NEET
Yes. NCERT states that all living organisms — from prokaryotes to the most complex plants and animals — can sense their surroundings and respond to changes in them (physical, chemical or biological). This ability to sense and respond is called consciousness. Because every living thing shows it, NCERT calls consciousness the defining property of living organisms. Non-living things do not sense or respond on their own.
Consciousness = awareness of the surroundings (sensing and responding to the outside world). This is present in ALL living organisms. Self-consciousness = awareness of one's own self. This is present in only human beings. So a plant bending toward light is showing consciousness, but a human thinking 'I exist' is showing self-consciousness. NEET often tests this exact line: humans are the only self-conscious organisms.
Read the question carefully. NCERT gives TWO strong answers depending on wording. Metabolism is called the defining feature of all living organisms 'without exception' (a chemical/technical definition). Consciousness is called the defining property of living organisms because all organisms sense and respond to their environment. Both statements appear in NCERT and both can be marked correct in different questions. If the option says 'consciousness — awareness of surroundings' it is a valid defining property; do not reject it just because you memorised only metabolism.
In the NCERT sense, yes. Consciousness here does NOT mean thinking or a brain. It only means the ability to sense the environment and respond. Plants sense light (they bend toward it), gravity, touch (Mimosa folds its leaves), water and seasons. That sensing-and-responding is what NCERT calls consciousness. It is different from human self-awareness.
Yes, according to NCERT. All living organisms are conscious (aware of surroundings), but human beings are the only organisms who are self-conscious — aware of their own self. This is a favourite one-line fact for NEET, so remember: 'Only humans are self-conscious.'
Use a checklist. Growth, reproduction, metabolism, cellular organisation and consciousness are all listed by NCERT. Growth and reproduction have exceptions (mules can't reproduce, non-living things can grow externally). Metabolism has NO exception. Consciousness is unique because it adds the human-only twist of self-consciousness. Hook: 'Sense the world = alive; sense yourself = human.'
Try the real previous-year questions from this chapter — each with the answer and a full solution.
Consciousness is the ability of a living organism to sense its surroundings and respond to changes in the environment — physical, chemical or biological. NCERT calls it the defining property of living organisms.
Human beings. All living organisms are conscious (aware of surroundings), but only humans are self-conscious (aware of their own self).
No. Metabolism is the sum of all chemical reactions in the body and is the defining feature with no exception. Consciousness is the ability to sense and respond to the environment. Both are described by NCERT as defining properties of living organisms.
Yes. From bacteria to plants to animals, every living organism can sense stimuli and respond to them. This universal sensing-and-responding is why consciousness is called a defining property.
No. In NCERT, consciousness only means sensing the environment and responding to it. Plants and single-celled organisms have no brain but still sense light, chemicals and touch, so they are consciousness in this sense.
