Plus One / 12th Botany - Book Back Answers - Chapter 6 - English Medium
Tamil Nadu Board 12th Standard Botany - Chapter 6: Book Back Answers and Solutions
This post covers the book back answers and solutions for Chapter 6 – Botany from the Tamil Nadu State Board 12th Standard Botany textbook. These detailed answers have been carefully prepared by our expert teachers at KalviTips.com.
We have explained each answer in a simple, easy-to-understand format, highlighting important points step by step under the relevant subtopics. Students are advised to read and memorize these subtopics thoroughly. Once you understand the main concepts, you’ll be able to connect other related points with real-life examples and confidently present them in your tests and exams.
By going through this material, you’ll gain a strong understanding of Botany Chapter 6 along with the corresponding book back questions and answers (PDF format).
Question Types Covered:
- 1 Mark Questions: Choose the correct answer, Fill in the blanks, Identify the correct statement, Match the following
- 2 Mark Questions: Answer briefly
- 3, 4, and 5 Mark Questions: Answer in detail
All answers are presented in a clear and student-friendly manner, focusing on key points to help you score full marks.
All the best, Class 12 students! Prepare well and aim for top scores. Thank you!
Unit 6 - Principles of Ecology
I. Multiple Choice Questions
1. Arrange the correct sequence of ecological hierarchy starting from lower to higher level.
a) Individual organism → Population Landscape → Ecosystem
b) Landscape → Ecosystem → Biome → Biosphere
c) community → Ecosystem → Landscape → Biome
d) Population → organism → Biome → Landscape
Answer Key:
c) community → Ecosystem → Landscape → Biome
2. Ecology is the study of an individual species is called
i) Community ecology
ii) Autecology
iii) Species ecology
iv) Synecology
a) i only
b) ii only
c) i and iv only
d) ii and iii only
Answer Key:
d) ii and iii only
3. A specific place in an ecosystem, where an organism lives and performs its functions is
a) habitat
b) niche
c) landscape
d) biome
Answer Key:
b) niche
4. Read the given statements and select the correct option.
i) Hydrophytes possess aerenchyma to support themselves in water.
ii) Seeds of Viscum are positively photoblastic as they germinate only in presence of light.
iii) Hygroscopic water is the only soil water available to roots of plant growing in soil as it is present inside the micropores.
iv) High temperature reduces use of water and solute absorption by roots.
a) i, ii, and iii only
b) ii, iii and iv
c) ii and iii only
d) i and ii only
Answer Key:
d) i and ii only
5. Which of the given plant produces cardiac glycosides?
a) Calotropis
b) Acacia
c) Nepenthes
d) Utricularia
Answer Key:
a) Calotropis
6. Read the given statements and select the correct option.
i) Loamy soil is best suited for plant growth as it contains a mixture of silt, sand and clay.
ii) The process of humification is slow in case of organic remains containing a large amount of lignin and cellulose.
iii) Capillary water is the only water available to plant roots as it is present inside the micropores.
iv) Leaves of shade plant have more total chlorophyll per reaction centre, low ratio of chl a and chl b are usually thinner leaves.
a) i, ii and iii only
b) ii, iii and iv only
c) i, ii and iv only
d) ii and iii only
Answer Key:
c) i, ii and iv only
7. Read the given statements and select the correct option.
Statement A : Cattle do not graze on weeds of Calotropis.
Statement B : Calotropis have thorns and spines, as defense against herbivores.
a) Both statements A and B are incorrect.
b) Statement A is correct but statement B is incorrect.
c) Both statements A and B are correct but statement B is not the correct explanation of statement A.
d) Both statements A and B are correct and statement B is the correct explanation of statement A.
Answer Key:
b) Statement A is correct but statement B is incorrect.
8. In soil water available for plants is
a) gravitational water
b) chemically bound water
c) capillary water
d) hygroscopic water
Answer Key:
c) capillary water
9. Read the following statements and fill up the blanks with correct option.
i) Total soil water content in soil is called _________________
ii) Soil water not available to plants is called _________________
iii) Soil water available to plants is called _________________
Answer Key:
(a) Holard Echard Chresard
10. Column I represent the size of the soil particles and Column II represents type of soil components. Which of the following is correct match for the Column I and Column IL
Column - I Column - II
I). 0.2 to 2.00 mm i) Slit soil
II) Less than 0.002 mm ii) Clayey soil
III) 0.002 to 0.02 mm iii) Sandy soil
IV) 0.002 to 0.2 mm iv) Loamy soil
Answer Key:
c) iii ii i iv
11. The plant of this group are adapted to live partly in water and partly above substratum and free from water
a) Xerophytes
b) Mesophytes
c) Hydrophytes
d) Halophytes
Answer Key:
d) Halophytes
12 . Identify the A, B, C and D in the given table
Answer Key:
a) (+) Parasitism (-) Amensalism
13. Ophrys an orchid resembling the female of an insect so as to able to get pollinated is due to phenomenon of
a) Myrmecophily
b) Ecological equivalents
c) Mimicry
d) None of these
Answer Key:
c) Mimicry
14. A free living nitrogen fixing cyanobacterium which can also form symbiotic association with the water fern Azolla
a) Nostoc
b) Anabaena
c) chlorella
d) Rhizobium
Answer Key:
b) Anabaena
15. Pedogenesis refers to
a) Fossils
b) Water
c) Population
d) Soil
Answer Key:
d) Soil
16. Mycorrhiza promotes plant growth by
a) Serving as a plant growth regulators
b) Absorbing inorganic ions from soil
c) Helping the plant in utilizing atmospheric nitrogen
d) Protecting the plant from infection
Answer Key:
b) Absorbing inorganic ions from soil
17. In a fresh water environment like pond, rooted autotrophs are
a) Nymphaea and typha
b) Ceratophyllum and Utricularia
c) Wolffia and pistia
d) Azolla and lemna
Answer Key:
a) Nymphaea and typha
18. Match the following and choose the correct combination from the options given below:
Answer Key:
a) Individual organism → Population Landscape → Ecosystem
b) Landscape → Ecosystem → Biome → Biosphere
c) community → Ecosystem → Landscape → Biome
d) Population → organism → Biome → Landscape
Answer Key:
c) community → Ecosystem → Landscape → Biome
2. Ecology is the study of an individual species is called
i) Community ecology
ii) Autecology
iii) Species ecology
iv) Synecology
a) i only
b) ii only
c) i and iv only
d) ii and iii only
Answer Key:
d) ii and iii only
3. A specific place in an ecosystem, where an organism lives and performs its functions is
a) habitat
b) niche
c) landscape
d) biome
Answer Key:
b) niche
4. Read the given statements and select the correct option.
i) Hydrophytes possess aerenchyma to support themselves in water.
ii) Seeds of Viscum are positively photoblastic as they germinate only in presence of light.
iii) Hygroscopic water is the only soil water available to roots of plant growing in soil as it is present inside the micropores.
iv) High temperature reduces use of water and solute absorption by roots.
a) i, ii, and iii only
b) ii, iii and iv
c) ii and iii only
d) i and ii only
Answer Key:
d) i and ii only
5. Which of the given plant produces cardiac glycosides?
a) Calotropis
b) Acacia
c) Nepenthes
d) Utricularia
Answer Key:
a) Calotropis
6. Read the given statements and select the correct option.
i) Loamy soil is best suited for plant growth as it contains a mixture of silt, sand and clay.
ii) The process of humification is slow in case of organic remains containing a large amount of lignin and cellulose.
iii) Capillary water is the only water available to plant roots as it is present inside the micropores.
iv) Leaves of shade plant have more total chlorophyll per reaction centre, low ratio of chl a and chl b are usually thinner leaves.
a) i, ii and iii only
b) ii, iii and iv only
c) i, ii and iv only
d) ii and iii only
Answer Key:
c) i, ii and iv only
7. Read the given statements and select the correct option.
Statement A : Cattle do not graze on weeds of Calotropis.
Statement B : Calotropis have thorns and spines, as defense against herbivores.
a) Both statements A and B are incorrect.
b) Statement A is correct but statement B is incorrect.
c) Both statements A and B are correct but statement B is not the correct explanation of statement A.
d) Both statements A and B are correct and statement B is the correct explanation of statement A.
Answer Key:
b) Statement A is correct but statement B is incorrect.
8. In soil water available for plants is
a) gravitational water
b) chemically bound water
c) capillary water
d) hygroscopic water
Answer Key:
c) capillary water
9. Read the following statements and fill up the blanks with correct option.
i) Total soil water content in soil is called _________________
ii) Soil water not available to plants is called _________________
iii) Soil water available to plants is called _________________
|
(i)
|
(ii)
|
(iii)
|
|
|
(a)
|
Holard
|
Echard
|
Chresard
|
|
(b)
|
Echard
|
Holard
|
Chresard
|
|
(c)
|
Chresard
|
Echard
|
Holard
|
|
(d)
|
Holard
|
Chresard
|
Echard
|
(a) Holard Echard Chresard
10. Column I represent the size of the soil particles and Column II represents type of soil components. Which of the following is correct match for the Column I and Column IL
Column - I Column - II
I). 0.2 to 2.00 mm i) Slit soil
II) Less than 0.002 mm ii) Clayey soil
III) 0.002 to 0.02 mm iii) Sandy soil
IV) 0.002 to 0.2 mm iv) Loamy soil
|
I
|
II
|
III
|
IV
|
|
|
a)
|
ii
|
iii
|
iv
|
i
|
|
b)
|
iv
|
i
|
iii
|
ii
|
|
c)
|
iii
|
ii
|
i
|
iv
|
|
d)
|
None of the above
|
|||
c) iii ii i iv
11. The plant of this group are adapted to live partly in water and partly above substratum and free from water
a) Xerophytes
b) Mesophytes
c) Hydrophytes
d) Halophytes
Answer Key:
d) Halophytes
12 . Identify the A, B, C and D in the given table
|
Interaction
|
Effects on species X
|
Effects on species Y
|
|
Mutualism
|
A
|
(+)
|
|
A
|
(+)
|
(-)
|
|
Competition
|
(-)
|
C
|
|
D
|
(-)
|
0
|
|
A
|
B
|
C
|
D
|
|
|
a)
|
(+)
|
Parasitism
|
(-)
|
Amensalism
|
|
b)
|
(-)
|
Mutalism
|
(+)
|
Competition
|
|
c)
|
(+)
|
Competition
|
0
|
Mutalism
|
|
d)
|
0
|
Amensalism
|
(+)
|
Parasitism
|
a) (+) Parasitism (-) Amensalism
13. Ophrys an orchid resembling the female of an insect so as to able to get pollinated is due to phenomenon of
a) Myrmecophily
b) Ecological equivalents
c) Mimicry
d) None of these
Answer Key:
c) Mimicry
14. A free living nitrogen fixing cyanobacterium which can also form symbiotic association with the water fern Azolla
a) Nostoc
b) Anabaena
c) chlorella
d) Rhizobium
Answer Key:
b) Anabaena
15. Pedogenesis refers to
a) Fossils
b) Water
c) Population
d) Soil
Answer Key:
d) Soil
16. Mycorrhiza promotes plant growth by
a) Serving as a plant growth regulators
b) Absorbing inorganic ions from soil
c) Helping the plant in utilizing atmospheric nitrogen
d) Protecting the plant from infection
Answer Key:
b) Absorbing inorganic ions from soil
17. In a fresh water environment like pond, rooted autotrophs are
a) Nymphaea and typha
b) Ceratophyllum and Utricularia
c) Wolffia and pistia
d) Azolla and lemna
Answer Key:
a) Nymphaea and typha
18. Match the following and choose the correct combination from the options given below:
|
Column I
(Interaction)
|
Column II
(Examples)
|
|
I. Mutualism
II. Commensalism
III. Parasitism
IV. Predation
|
i). Trichoderma and Penicillium
ii). Balanophora, Orobanche
iii). Orchids and Ferns
iv). Lichen and
|
|
|
I
|
II
|
III
|
IV
|
V
|
|
a)
|
i
|
ii
|
iii |
iv
|
v
|
|
b)
|
ii
|
iii
|
iv
|
v
|
i
|
|
c)
|
iii
|
iv
|
v
|
i
|
ii
|
|
d)
|
iv
|
iii
|
ii |
v
|
i
|
d) iv iii ii v i
19. Sticky glands of Boerhaavia and Cleome support
a) Anemochory
b) Zoochory
c) Autochory
d) Hydrochory
Answer Key:
b) Zoochory
19. Sticky glands of Boerhaavia and Cleome support
a) Anemochory
b) Zoochory
c) Autochory
d) Hydrochory
Answer Key:
b) Zoochory
II. Short Answer Questions
12th bio botanyIII. Long Answer Questions
12th bio botanyIV. Exercise
12thbio botany
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