1. Living vs Non-living (High-level)
Living things:
- Show growth.
- Can reproduce.
- Respire & use energy.
- Respond to stimuli.
- Made up of cells.
2. Cell – Basic Unit of Life
- Cell: structural & functional unit of life.
- Organisms can be:
- Unicellular – one cell (e.g., Amoeba, bacteria)
- Multicellular – many cells (humans, plants)
- Cell membrane
- Cytoplasm
- Nucleus
हिंदी: शरीर की “इमारत” की सबसे छोटी ईंट = Cell
इसी से tissues, organs और पूरा शरीर बनता है।
3. Tissues, Organs & Systems
Hierarchy:
- Cells → Tissues → Organs → Organ systems → Organism
- Muscle cells → muscle tissue → heart → circulatory system → human body.
4. Human Body – Main Organ Systems (NDA Overview)
1) Digestive system: mouth, oesophagus, stomach, intestines; function – digestion & absorption of food.
2) Respiratory system: nose, trachea, lungs; function – exchange of gases (O₂ in, CO₂ out).
3) Circulatory system: heart, blood, blood vessels; function – transport of oxygen, nutrients, wastes.
4) Excretory system: kidneys, ureters, bladder; function – removal of waste (urine).
5) Nervous system: brain, spinal cord, nerves; function – coordination & response.
6) Skeletal & muscular systems: bones and muscles; support, movement, protection of organs.
2) Respiratory system: nose, trachea, lungs; function – exchange of gases (O₂ in, CO₂ out).
3) Circulatory system: heart, blood, blood vessels; function – transport of oxygen, nutrients, wastes.
4) Excretory system: kidneys, ureters, bladder; function – removal of waste (urine).
5) Nervous system: brain, spinal cord, nerves; function – coordination & response.
6) Skeletal & muscular systems: bones and muscles; support, movement, protection of organs.
📘 Practice Questions (NDA Style)
1. Structural and functional unit of life is:
a) Tissue
b) Cell
c) Organ
d) System
2. Amoeba is:
a) Multicellular
b) Unicellular
c) Tissue
d) Virus
3. Kidney is part of:
a) Digestive system
b) Respiratory system
c) Excretory system
d) Nervous system
4. Which system transports oxygen in the body?
a) Digestive
b) Circulatory
c) Respiratory
d) Excretory
5. Brain is part of:
a) Skeletal system
b) Nervous system
c) Muscular system
d) Digestive system
a) Tissue
b) Cell
c) Organ
d) System
2. Amoeba is:
a) Multicellular
b) Unicellular
c) Tissue
d) Virus
3. Kidney is part of:
a) Digestive system
b) Respiratory system
c) Excretory system
d) Nervous system
4. Which system transports oxygen in the body?
a) Digestive
b) Circulatory
c) Respiratory
d) Excretory
5. Brain is part of:
a) Skeletal system
b) Nervous system
c) Muscular system
d) Digestive system
Answers:
1 – b
2 – b
3 – c
4 – b
5 – b
1 – b
2 – b
3 – c
4 – b
5 – b
Quick Recap | सार
Now you should be able to:
- Recall the most important ideas of this topic.
- Solve typical NDA-style questions from this chapter.
- Spot and avoid common traps used in competitive exams.
Self-check: 3–4 random questions उठा कर देखिए – अगर आसानी से हो रहे हैं, तो chapter strong है।
Common Exam Mistakes | आम गलतियाँ
- Concept ठीक से clear न करना और सीधे रटने की कोशिश करना।
- Question पूरी तरह पढ़े बिना answer mark कर देना।
- Figures, dates, या formulas को last step में verify न करना।
NDA में smart strategy यह है कि आसान वाले सवाल पहले, doubtful बाद में – और silly mistakes से बचना सबसे ज़रूरी है।