Test: Tissue- 2 - Class 9 MCQ

Cartilage is not found in kidney. As cartilage is a structural component  of our body act as connective tissue which  is not required in the kidney. They are flexible connective tissue mainly found in ribs, ear, nose  etc.

Cartilage is the tissue that smoothes bone surfaces at joints. It is a type of connective tissue. It is an elastic tissue.It  protects the joints . It  is present at the joints. Nose and
Ear  also has cartilage tissues.
 

Type of Epithelial Cells Responsible for Absorption in the Intestine
The type of epithelial cells responsible for absorption in the intestine are columnar epithelium. Here is a detailed explanation:
1. Structure of Columnar Epithelium:
- Columnar epithelium is a single layer of tall, rectangular-shaped cells.
- These cells have elongated nuclei located near the base of the cells.
- They are tightly packed together, forming a barrier between the lumen (inside) of the intestine and the underlying tissue.
2. Function of Columnar Epithelium:
- Columnar epithelium is specialized for absorption and secretion.
- The tall shape of the cells increases the surface area available for absorption.
- Microvilli, tiny finger-like projections on the surface of the cells, further increase the surface area for absorption.
3. Absorption in the Intestine:
- The intestine is responsible for the absorption of nutrients from the digested food.
- The columnar epithelial cells lining the intestine play a crucial role in this process.
- Nutrients such as sugars, proteins, and fats are absorbed by these cells through active transport and diffusion.
- Once absorbed, the nutrients enter the bloodstream and are transported to various parts of the body to provide energy and support cellular functions.
4. Adaptations of Columnar Epithelium for Absorption:
- The presence of microvilli greatly increases the surface area for absorption.
- The columnar shape of the cells allows for efficient absorption and secretion.
- The cells are held together by tight junctions, preventing leakage of absorbed nutrients.
In conclusion, columnar epithelial cells are responsible for the absorption of nutrients in the intestine. Their specialized structure and adaptations enable efficient absorption of nutrients from the digested food.

Skeletal muscle fibers are cylindrical, multinucleated, striated, and under voluntary control. Smooth muscle cells are spindle shaped, have a single, centrally located nucleus, and lack striations. They are called involuntary muscles. Cardiac muscle has branching fibers, one nucleus per cell, striations, and intercalated disks. Its contraction is not under voluntary control.

Incorrect Sentence:
The incorrect sentence is C: "Apical and intercalary meristems are permanent tissues."
Explanation:
Here is a detailed explanation of why sentence C is incorrect:
- Apical and intercalary meristems are not permanent tissues. They are actually examples of meristematic tissues, which are responsible for plant growth and development.
- Meristematic tissues are made up of actively dividing cells and are found in the growing regions of plants, such as the tips of roots and shoots.
- These tissues are responsible for the production of new cells, which then differentiate into various specialized cell types.
- Unlike permanent tissues, meristematic tissues do not have a specific structure or function. They are constantly dividing and giving rise to new cells.
- Permanent tissues, on the other hand, are derived from meristematic tissues and have specific functions in the plant.
- Examples of permanent tissues include parenchyma, collenchyma, and sclerenchyma, which have specialized structures and functions.
Therefore, the correct sentence should be:
"C: Apical and intercalary meristems are meristematic tissues."

The dead element present in the phloem is phloem fibres.
Phloem is a complex tissue in plants that is responsible for the transport of sugars, nutrients, and other organic molecules from the leaves to other parts of the plant. It is composed of several different cell types, including sieve tubes, companion cells, phloem parenchyma, and phloem fibres.
Here's a detailed explanation of each of these cell types and why phloem fibres are the dead element in the phloem:
1. Sieve tubes:
- Sieve tubes are the main conducting cells in the phloem.
- They are elongated cells that are connected end-to-end to form a continuous tube.
- Sieve tubes have sieve plates at their ends, which are perforated to allow the flow of sap.
- These cells are living but lack a nucleus, ribosomes, and other organelles.
2. Companion cells:
- Companion cells are closely associated with sieve tubes and provide metabolic support to them.
- They have a nucleus and other organelles, allowing them to carry out cellular functions.
- Companion cells are connected to sieve tubes through plasmodesmata, small channels that allow the exchange of materials.
3. Phloem parenchyma:
- Phloem parenchyma cells are living cells that are involved in storage and metabolism.
- They are relatively unspecialized and can perform various functions depending on their location in the plant.
4. Phloem fibres:
- Phloem fibres are long, slender cells that provide mechanical support to the phloem.
- Unlike sieve tubes, companion cells, and phloem parenchyma cells, phloem fibres are dead at maturity.
- They have thick secondary cell walls composed of cellulose, lignin, and other structural materials.
- Phloem fibres are responsible for maintaining the structural integrity of the phloem tissue.
In conclusion, among the different cell types present in the phloem, phloem fibres are the dead element. They provide mechanical support to the phloem tissue, but they lack cellular components and are non-functional in terms of metabolic activities.

Meristematic tissues in plants are:
- Localised and dividing cells: Meristematic tissues are found in specific regions of the plant, such as the tips of roots and shoots. These tissues consist of actively dividing cells, which contribute to the growth and development of the plant.
- Not limited to certain regions: While meristematic tissues are primarily found in the apical meristems (tips) of roots and shoots, they can also be present in other parts of the plant, such as the lateral meristems (cambium) and intercalary meristems (in between mature tissues).
- Growing in volume: As meristematic cells divide, they contribute to the growth of the plant in terms of both length and width. This allows the plant to increase in size and develop new organs and tissues.
- Permanent: Meristematic tissues are continuously active throughout the lifespan of the plant. They are responsible for the production of new cells, which eventually differentiate into various specialized tissues, such as vascular tissue, epidermis, and ground tissue.
In conclusion, meristematic tissues in plants are localized and composed of dividing cells. They are not limited to certain regions and are responsible for the growth and development of the plant.

The mineral elements found in our bone making it hard are:
- Calcium: Calcium is the most abundant mineral in the body and plays a crucial role in the formation and maintenance of strong bones. It provides the basic structure and strength to our bones.
- Phosphorus: Phosphorus works together with calcium to form a mineral complex called hydroxyapatite, which is the main component of bone. It helps in the mineralization of bones, making them hard and strong.
- Sodium: Sodium is an essential mineral that helps in maintaining the balance of fluids in our body. While it is present in small amounts in our bones, it does not contribute significantly to the hardness of bones.
- Potassium: Potassium is another mineral that is present in small amounts in bones. It helps in regulating the acid-base balance in the body but does not directly contribute to bone hardness.
Therefore, the correct answer is B: Calcium and phosphorus. These two minerals work together to provide the necessary strength and hardness to our bones.

Epithelial tissue gives rise to glands in the body. They line the surface of various ducts, glands and organs. This type of tissue is also known as glandular Epithethillum increase by mitosis.

Epidermis is present as outermost layer of plant body such as leaves, flowers, stem and root. It is covered with cuticle (a waterproof layer of waxy substance cutin) The main function of epidermis is to protect the plant from desiccation and infection. In fact, cuticle of epidermis helps to reduce water loss by evaporation from the plant surface and also helps in preventing the entry of pathogen (bacteria, fungi etc.). The aerial surface of many plant bear cutinised hair (trichomes) to reduce transpiration.