1. A
   All of these
2. B
   P receives nerve impulse from Q and conveys it to other cells.
3. C
   R is called node of Ranvier.
4. D
   P conducts impulse away from cyton while S conducts impulse towards cyton.

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1. A
   The cell walls are not lignified in sclerenchyma.
2. B
   The figure shows transverse section instead of longitudinal section of tissue.
3. C
   Instead of simple pit pore, it should be bordered pit.
4. D
   The nucleus and cytoplasm are not shown.

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1. A
   Angular collenchyma, in which wall thickenings are present at the angles
2. B
   Xylem vessel that forms long channels for conduction of water and minerals
3. C
   Phloem parenchyma with abundant food reserve
4. D
   Sclerenchyma, in which uniform wall thickenings are present

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1. A
   Adipose tissue
2. B
   Striated muscle tissue
3. C
   Ciliated columnar epithelial tissue
4. D
   Areolar tissue

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1. A
   The parts labelled 'a', 'b' and 'c' all possess photosynthetic pigments such as chlorophyll.
2. B
   The part labelled 'a' is the site of dark reaction.
3. C
   The part labelled 'c' is called granum.
4. D
   The part labelled 'b' is called intergranal thylakoid.

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1. A
   Onion cell
2. B
   Cheek cell
3. C
   Prokaryotic cell
4. D
   Amyloplast

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1. A
   Nucleoid (lacks true nucleus)
2. B
   True nucleus
3. C
   Nucleus without mitochondrial membrane
4. D
   Nucleus with nuclear membrane

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1. A
   Endoplasmic reticulum
2. B
   Mitochondria
3. C
   Lysosomes
4. D
   Golgi apparatus

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1. A
   Production of food
2. B
   It is an energy molecule
3. C
   It helps in cellular respiration
4. D
   It helps in cell division

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1. A
   1 - cell wall, 2 - Nucleoid, 3 - Cell membrane; Bacterial cell
2. B
   1 - cell wall, 2 - mitochondria, 3 - Cell membrane; Plant cell
3. C
   1 - cell membrane, 2 - nucleus, 3 - Cell wall; Animal cell
4. D
   1 - cell wall, 2 - nucleus, 3 - Cell membrane; Plant cell

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1. A
   Golgi apparatus, near nucleus
2. B
   Ribosome, on the endoplasmic reticulum
3. C
   Endoplasmic reticulum, cytoplasm
4. D
   Golgi apparatus, away from nucleus

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1. A
   Nucleus
2. B
   Chloroplast
3. C
   Mitochondria
4. D
   Lysosome

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1. A
   A - Turgid plant cell; B - plasmolysed plant cell. A will shrink up and B will swell and regain the size.
2. B
   A - plasmolysed cell; B - turgid plant cell. A will swell up and B will shrink.
3. C
   A - turgid cell; B - plasmolysed plant cell. A will swell up and B will shrink.
4. D
   A - plasmolysed cell; B - turgid plant cell. A will shrink up and B will swell and regain the original shape.

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1. A
   Lysosome, cell digestion
2. B
   Nucleus, controls lipid synthesis
3. C
   Ribosome, helps in protein synthesis
4. D
   Golgi bodies, secretion of enzymes

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1. A
   The rate of contraction increases as osmolarity decreases because the amount of water entering X by osmosis increases.
2. B
   In an isotonic solution there is no diffusion of water in or out of X, so the contraction rate is zero.
3. C
   At higher osmolarity, more salt diffuses into X, therefore lower rates of contraction are required.
4. D
   The contractile vacuole is less efficient in a solution of high osmolarity because of reduced respiration and less production of ATP.

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1. A
   The parts labelled 'a', 'b' and 'c', all possess photosynthetic pigments such as chlorophyll.
2. B
   The part labelled 'a' is the site of dark reaction.
3. C
   The part labelled 'c' is called granum.
4. D
   The part labelled 'b' is called intergranal thylakoid.

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1. A
   Y contains respiratory enzymes, lipids, RNA, etc.
2. B
   Z contains respiratory enzymes, lipids, RNA, etc.
3. C
   Y is arranged in a characteristic pattern in different cells and bears oxysomes.
4. D
   X is freely permeable to small molecules and ions.

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1. A
   a lobed, bean-shaped organelle
2. B
   a stack of curved flattened sacs with budding vesicles (Golgi apparatus)
3. C
   a round, whorled organelle
4. D
   an oval organelle containing stacks of disc-shaped thylakoids (chloroplast)

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1. A
   From solution 1 to solution 2
2. B
   Both from solution 1 to solution 2 and from solution 2 to solution 1
3. C
   From solution 2 to solution 1
4. D
   No movement will take place

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1. A
   S
2. B
   P
3. C
   R
4. D
   Q

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1. A
   Ecosystem
2. B
   Food web
3. C
   Ecological pyramid
4. D
   Food chain

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1. A
   control CO₂ emissions in the environment
2. B
   control water pollution
3. C
   reduce CFC production
4. D
   conserve biodiversity

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1. A
   Grass, wheat and mango
2. B
   Goat, cow and elephant
3. C
   Grass, fish and goat
4. D
   Grass, goat and human

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1. A
   A community of plants and animals only
2. B
   A natural ecosystem
3. C
   An artificial ecosystem
4. D
   A biomes

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1. A
   Tiger will start eating grass.
2. B
   The population of grass will decrease.
3. C
   The population of tiger will decreases and the population of grass will increase.
4. D
   The population of tiger will increase.

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