Question 1.
What is a tissue?
Solution:
A tissue may be defined as a group or collection of similar or dissimilar cells that perform dr help to perform a common function and have common orgin.

Question 2.
What is the utility of tissues in multicellular organism?
Solution:
The utility of tissues in multicellular organism is given below:

• Division of labour: Tissues bring about division of labour in multicellular organ-isms. It increases efficiency.
• Higher organisation: Tissues become organised to form organs and organ systems.
• Individual cells: Work load of individual cells has decreased.
• Higher survival: Because of division of labour, higher efficiency,and organisation, the multicellular organisms have high survival.

Question 3.
Name the types of simple tissues.
Solution:
There are three types of simple tissues. These are parenchyma, collenchyma and sclerenchyma.

Question 4.
Where is apical meristem found?
Solution:
Apical meristem occurs at root and stem tips.

Question 5.
Which tissue makes up the husk of coconut?
Solution:
Sclerenchyma (fibres) makes up the husk of coconut.

Question 6.
What are the constituents of the phloem?
Solution:
The constituents of the phloem are sieve tubes, companion cells, phloem parenchyma and phloem fibres.

Question 7.
What are the functions of areolar tissue?
Solution:
Areolar tissue fills the space inside the organs, supports internal organs and helps in repair of tissues. It binds the skin with underlying parts.

Question 8.
Name the tissue responsible for movement in our body.
Solution:
Muscular and skeletal tissue are responsible for movement in our body.

Question 9.
What does a neuron look like?
Solution:
Neuron is a thread or hair like structure, with palm leaf shaped structure at one end.

Question 10.
Give three features of cardiac muscle.
Solution:
The three features of cardiac muscle are given below:

• Cardiac muscles show morphological characteristics of both striated and unstriated muscles.
• Intercalated discs are present in the cardiac muscle fibres.
• The muscles show rhythmic contractions, without fatigue.

NCERT Exercises

Question 1.
Define the term “tissue”.
Solution:
A tissue may be defined as a group or collection of similar or dissimilar cells that perform or help to perform a common function and have common orgin.

Question 2.
How many types of elements together make up the xylem tissue? Name them.
Solution:
Four types of elements together make up the xylem tissue. These elements are-

• tracheids,
• vessels,
• xylem parenchyma and
• xylem fibres.

Question 3.
How are simple tissues different from complex tissues in plants?
Solution:
Simple tissues are made up of only one type of cells, which look like each other. On the other hand, complex tissues are made up of more than one type of cells. Parenchyma, collenchyma and sclerenchyma are the examples of simple plant tissue whereas xylem and phloem are complex tissues.

Question 4.
Differentiate between parenchyma, collenchyma and sclerenchyma on the basis of their cell wall.
Solution:
On the basis of the cell wall, differences between parenchyma, collenchyma and sclerenchyma are-

	Parenchyma	collenchyma	Sclerenchyma
1.	Cell wall is thin.	Cell wall is thick at angles.	Cell wall hard, rigid, and uniformly thick.
2.	Made up of cellulose.	Made up of cellulose and pectin.	Made up of lignin – a waterproof material.

Question 5.
What are the functions of the stomata?
Solution:
Stomata are necessary for exchanging gases with the atmosphere. Transpiration (loss of water in the form of water vapour) also

Question 6.
Diagrammatically show the difference among three types of muscle fibres.
Solution:

Question 7.
What is the specific function of the cardiac muscle?
Solution:
The specific function of the cardiac muscle is rhythmic contraction and relaxation simultaneously throughout life without getting fatigued.

Question 8.
Differentiate among striated, unstriated and cardiac muscles on the basis of their structure and site/location in the body.
Solution:
The differences among striated, unstri-ated and cardiac muscles are as follows:

Striated muscles	Unstriated muscles	Cardiac muscles
1.	Each muscle is long, cylindrical, non-tapering and multi- nucleate.	Each muscle fibre is long, flattened, spindle shaped, tapering and uninucleate.	The fibres have centrally located one or two nuclei and transverse striations with light and dark bands. They are branched.
2.	Show striations.	Do not show striations.	Show transverse striations.
3.	Occur in the limbs, body wall and neck.	Occur in the walls of all tubular organs such as the stomach, intestines, blood vessels, breathing passages and the urino-genital ducts.	Occur only in the walls of the heart.

Question 9.
Draw a labelled diagram of a neuron.
Solution:

Question 10.
Name the following:

1. Tissue that forms inner lining of our mouth.
2. Tissue that connects muscle to bone in humans.
3. Tissue that transports food in plants.
4. Tissue that stores fat in our body.
5. Connective tissue with a fluid matrix.
6. Tissue present in the brain.

Solution:

1. Squamous epithelium, an epithelial tissue
2. Tendon
3. Phloem
4. Adipose tissue
5. Fluid connective tissue i.e., blood and lymph
6. Nervous tissue

Question 11.
Identify the type of tissue in the following: skin, bark of tree, bone, lining of kidney tubule, vascular bundle.
Solution:
Skin—Squamous epithelium Bark of tree—Epidermal tissue/cork Bone—Supportive connective tissue or
skeletal tissue Lining of kidney tubule—Ciliated epithelium Vascular bundle—Xylem and phloem (conducting tissue).

Question 12.
Name the regions in which parenchyma tissue is present.
Solution:
In small herbaceous plants, parenchyma makes up the bulk of the plant body. It is mainly found in the cortex, pith, ground tissue leaf, mesophyll and also in vascular bundles.

Question 13.
What is the role of epidermis in plants?
Solution:
It protects internal tissues against mechanical injury, parasites and also cold or heat. Thick cuticle, wax, epidermal hair and epidermis reduce loss of water from internal tissue. Epidermal cells of roots have hairs that greatly increase the absorptive surface areas for the absorption of water and nutrients.

Question 14.
How does the cork act as a protective tissue?
Solution:
The walls of cork cells are heavily thickened by the deposition of suberin. This structural characteristic helps the cork to protect and prevent from infection and mechanical injury. It also prevents desiccation, by preventing loss of water from the plant body.

Question 15.
Complete the table:

Solution: