NIOS Class 12 Biology Intext Solutions Chapter 7

NIOS Class 12 Biology Intext Solutions Chapter 7

INTEXT QUESTIONS 7.1

1. Name the part of plant which bears nodes, leaves, and flowers.

Ans: Stem

2. Lateral branch develops from which bud?

Ans: Axillary bud

3. Why is it difficult to break lateral roots and not lateral branches on stem?

Ans: Because lateral roots originate from the inner layer, that is, the pericycle (endogenous origin)

4. Roots are negatively phototropic and positively geotropic, what pattern of growth does the stem show?

Ans: Stem is positively phototropic and negatively geotropic. 

INTEXT QUESTIONS 7.2

1. Name the meristematic zone in which cells divide in all planes.

Ans: Corpus 

2. From which meristematic layer does the vascular tissue develop?

Ans: Procambium

3. Which structure gives rise to a lateral branch? Name the type of its origin.

Ans: Axillary buds give rise to lateral branches. Origin of lateral branches is exogenous (originating from outer layers i.e., endodermis).

4. What is the structure known as which covers the apical meristem of root but is absent in stem?

Ans: Axillary bud, exogenous root cap

INTEXT QUESTIONS 7.3

1. What are plants with weak stem trailing on the ground known as?

Ans: Creeper 

2. Name the modification to which Runner, Stolon, Offset, and Sucker belong.

Ans:  Sub-aerial.

3. What is a phylloclade with one or two internodes called?

Ans: Cladode.

4. ‘Haldi’ and onion belong to which category of stem modification, respectively?

Ans: Rhizome, Bulb

5. Match the items of column A with those of column B

Column A	Column B
(a) Tendril	(i) Protection
(b) Sucker	(ii) Perennation
(c) Thorns	(iii) Reproduction
(d) Bulb	(iv) Photosynthesis
(e) Phylloclade	(v) Climbing

Ans: (a) – (v) (b) – (iii) (c) – (i) (d) – (ii) (e) – (iv)

INTEXT QUESTIONS 7.4

1. Give one primary function of stem.

Ans: Conduction of water and minerals from the root to the leaf and the manufacture of food from the leaf to other parts of the plant.

2. How does sugarcane plant multiply?

Ans: Sugarcane multiplies by vegetative propagation, via stem cuttings from the plant planted to grow new plants. 

3. Match the following in column A with column B.

Column A	Column B
(a) Opuntia	(i) Conduction
(b) Duranta	(ii) Storage of food
(c) Ginger	(iii) Photosynthesis
(d) Potato	(iv) Perennation
(e) Stem	(v) Protection

Ans: (a) – (iii) (b) – (v) (c) – (iv) (d) – (ii) (e) – (i)

INTEXT QUESTIONS 7.5

1. Differentiate between conjoint and collateral vascular bundles.

Ans: Conjoint is when xylem and phloem are together in one bundle, collateral is when xylem and phloem are on the same radius.

2. What is the region between two vascular bundles in a dicot stem known as?

Ans: Medullary ray.

3. Where will you find radially arranged vascular bundles with exarch xylem?

Ans: Root

4. If you want to study the internal structure of a monocot and a dicot stem, name the plants you would select for the study.

Ans: Maize stem for monocot and sunflower for dicot stem

INTEXT QUESTIONS 7.6

1. Name the two lateral meristems which ‘are responsible for increase in girth of stem.

Ans: Cork cambium (phellogen) and vascular cambium

2. From which region does the interfascicular cambium develop?

Ans:  Medullary ray parenchyma

3. Define bark.

Ans: All the tissues outside the functional cork cambium are called bark.

4. Why are lenticels non-suberized?

Ans: It is through the lenticels that woody branches and tree trunks can undergo gaseous exchange. Thus, this region is non-suberized. 

5. The stems of grasses, and rice, remain weak and thin. Why?

Ans: The stems of grasses and rice remain weak, and this is due to the absence of secondary growth in their stems.

6. Which layers constitute the periderm? What is its function?

Ans: Phellogen, phelloderm, and phellem together constitute the periderm. Due to an internal increase in thickness, periderm replaces the epidermis, becomes protective in function.

INTEXT QUESTIONS 7.7

1. Which type of wood is formed when the cambium is less active?

Ans:  Late or summer wood

2. How can you determine the age of a tree?

Ans:  By counting the annual rings

3. Why is heart wood commercially more valuable?

Ans: As the heartwood is more durable, resistant to the attack of pathogens, it is commercially more valuable. 

4. Why does a tall tree stand erect even in strong wind and lashing rain? 

Ans: Stem gets this strength from sclerenchyma in hypodermis and its patches in the pericycle and secondary phloem, abundant lignified vessels, tracheids, and fibres in secondary xylem i.e., wood and sclereids in pith.

5. Define wood.

Ans: Wood is secondary xylem produced by the activity of vascular cambium in the dicot stem.

INTEXT QUESTIONS 7.8

1. Define venation.

Ans: Venation is the arrangement of veins and veinlets in the lamina of a leaf.

2. Differentiate between unicostate and multicostate venation.

Ans: Unicostate has one strong midrib giving out secondary veins like in feather. On the other hand, multicostate has many strong veins spreading out from a common point like fingers of a palm.

3. What is the type of venation found in peepal and palm leaves?

Ans: Reticulate, parallel 

4. Name the structure which arises in the axil of leaf.

Ans: Axillary bud

5. What is the prominent vein called which is present in the middle of lamina and runs from base to apex?

Ans: Midrib

INTEXT QUESTIONS 7.9

1. Name the structure to which the leaflets are attached in a compound leaf.

Ans: Rachis

2. What is the structure which helps you differentiate a leaf from a leaflet?

Ans: Presence of axillary bud in the leaf but not in the leaflet

3. What are the two types of compound leaves known as?

Ans: Pinnately and palmately compound leaf

INTEXT QUESTIONS 7.10

1. What is the type of phyllotaxy found in mango, ‘tulsi’, and guava plants?

Ans: Alternate, opposite-decussate; opposite-superposed.

2. Match the following items of column A with those of column B 

Column A	Column B
(a) Pitcher	(i) Photosynthesis
(b) Spines	(ii) Climbing
(c) Phyllode	(iii) Trapping insects
(d) Tendril	(iv) Protection

Ans: (a) – (iii) (b) – (iv) (c) – (i) (d) – (ii)

3. Give two examples of insectivorous plants.

Ans: Pitcher plant; bladderwort

4. Water chestnut shows two different types of leaves on the same plant. What is such a condition known as?

Ans: Heterophylly

INTEXT QUESTIONS 7.11

1. How is the mesophyll tissue of dicot leaf different from that of monocot leaf? What is its function?

Ans: Mesophyll is differentiated into palisade and spongy tissue in a dicot leaf, but is composed of only spongy tissue in a monocot leaf. Mesophyll consists of chloroplast-containing parenchyma (chlorenchyma) and is responsible for carrying out photosynthesis.

2. Where are stomata located in a grass leaf?

Ans:  In both surfaces of the leaf.

3. Name the structure through which plants growing in humid areas get rid of excess water in liquid form.

Ans: Hydathodes

4. Match the following items of column A with those of column B

Column A	Column B
(a) Bulliform cells	(i) Protection
(b) Transport of water and mineral salts	(ii) Guttation
(c) Stomata only on lower surface	(iii) Monocot leaf
(d) Hydathode	(iv) Dicot leaf
(e) Hair	(v) Stomata
(f) Exchange of gases	(vi) Xylem

Ans: 

(a) – (iii) 

(b) – (vi) 

(c) – (iv) 

(d) – (ii) 

(e) – (i) 

(f) – (v)

INTEXT QUESTIONS 7.12

1. What is the collection of sepals and petals respectively known as?

Ans: Calyx, Corolla

2. Match the following items of column A with those of column B

Column A	Column B
(a) Flower	(i) China rose
(b) Polycarpellary	(ii) Pollination
(c) Petals	(iii) Reproductive organ
(d) Monodelphous	(iv) Many carpels
(e) Carpel	(v) Modified shoot

Ans: (a) – (v) (b) – (iv) (c) – (ii) (d) – (i) (e) – (iii)

3. Define placentation.

Ans: Placentation is the manner in which placentae are distributed in the ovary. The placenta is the point of attachment of the ovules (or future seeds) in the ovary.

4. Name the type of placentstion where ovary is many chambered and ovules are arranged on the central axis.

Ans: Axile

INTEXT QUESTIONS 7.13

1. What is a cyamose inflorescence?

Ans: When the main axis ends in a flower, and the growth is limited.

2. Give one difference between Raceme and Spike.

Ans:  Flowers are stalked in a raceme but sessile in a spike.

3. Define inflorescence.

Ans: Inflorescence is the arrangement of flowers on the floral axis called the peduncle. Inflorescence could be terminal or axillary.

4. Name the type of inflorescence found in sunflower and Figs.

Ans: Capitulum, Hypanthodium

INTEXT QUESTIONS 7.14

l. Define Fruit.

Ans: Fruit is a ripened ovary that develops after fertilization

2. Give two examples of false fruits.

Ans: Apple, pear

3. What is the fruit wall known as which is formed by the ovary wall?

Ans: Pericarp

4. Give the names of three layers of pericarp of a fleshy fruit.

Ans: Epicarp, mesocarp, endocarp

5. Match the following of column A with that in column B

Column A	Column B
(a) Apple	(i) Berry
(b) Hesperidium	(ii) Mesocarp
(c) Mango-edible part	(iii) Endosperm
(d) Coconut -edible part	(iv) Orange
(e) Tomato	(v) False Fruit

Ans: (a) – (v) (b) – (iv) (c) – (ii) (d) – (iii) (e) – (i)

Additional Study Materials

• NIOS Class 12 Biology Terminal Questions Answers!
• Chapter 01 Intext Solutions
• Chapter 02 Intext Solutions
• Chapter 03 Intext Solutions
• Chapter 04 Intext Solutions
• Chapter 05 Intext Solutions
• Chapter 06 Intext Solutions