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Simple epithelium is composed of one layer of cells, while compound epithelium is composed of more than one layer of cells.

Chondrocytes

Psudostratified Epithelium is the epithelial tissue made up of a single layer of columnar cells, but appears two layered because some cells are shorter than others and have their nuclei at different levels. It is located in trachea and bronchi.

• tip of nose
• pinna of ear
• between adjacent vertebrae in the vertebral column
• joints in the limbs

a. Osteomalacia

b. anaemia

(c) Vitamin C

1. Protein.

2. Scurvy

3. Anaemia.

4. Virus.

\(\alpha=\frac{ΔI}{IΔT}\)

From I observation,

\(\alpha=\frac{4\times10^{-4}}{2\times10}\)

\(=2\times10^{-5}C^{-1}\)

For II, observation   Δl=\(\alpha/ΔT \)

= 2 × 10^-5 × 1 × 1 

= 2 × 10^-4 ≠ 4 × 10^-4 m

For III, observation    

Δl=\(\alpha/ΔT \)

= 2 × 10^-5 × 2 × 20 

= 8 × 10^-4 m 

= 2 × 10^-4 m

For IV, observation  

 Δl=\(\alpha/ΔT \)

= 2 × 10^-5 × 3 × 10 

= 6 × 10^-4 m = 6 × 10^-4 m 

Therefore, IV observation is correct and II, III are wrong

1. – d 

2. – e 

3. – b

4. – a 

5. – c

(a) Parenchyma

(C) vascular cambium

1. Xylem is the water conducting tissue in higher plants. It is a dead complex tissue. It also provides mechanical strength to the plant body. 

Components of xylem are tracheids, vessels, xylem parenchyma and xylem fibres. 

2. Tracheids: 

a. These are elongated, tubular and dead cells (without protoplasm).

b. The ends are oblique and tapering. 

c. The cell walls is unevenly thickened and lignified. This provides mechanical strength. 

d. Tracheids contribute 95% of wood in gymnosperms and 5% in angiosperms. 

e. The different types of thickening patterns are seen on their walls such as annular (in the form of rings), spiral (in the form of spring/helix), scalariform (ladder like) and pitted (small circular area). Pitted is the most advanced type of thickening which may be simple or bordered. 

3. Vessels: 

a. Vessels are longer than tracheids with perforated or dissolved ends and formed by union of several vessels end to end. 

b. These are involved in conduction of water and minerals. 

c. Their lumen is wider than tracheids and the thickening is due to lignin and similar to tracheids. 

d. In monocots, vessels are rounded where as they are angular in dicot angiosperms. 

e. The first formed xylem vessels (protoxylem) are small and have either annular or spiral thickenings while latter formed xylem vessels are larger (metaxylem) and have reticulate or pitted thickenings.

f. When protoxylem is arranged towards pith and metaxylem towards periphery it is called as endarch e. g. in stem and when the position is reversed as in the roots is called as exarch. 

4. Xylem parenchyma: 

a. Xylem parenchyma cells are small associated with tracheids and vessels.

b. This is the only living tissue among this complex tissue. 

c. The function is to store food (starch) and sometimes tannins. 

d. Xylem parenchyma are involved in lateral or radial conduction of water or sap. 

5. Xylem fibres: 

a. Xylem fibres are sclerenchymatous cells and serve mainly mechanical support. These are called wood fibres. 

b. These are also elongated, narrow and spindle shaped.

c. Cells are tapering at both the ends and their walls are lignified.

This is the only living tissue among this complex tissue.

(i) The pancreas secretes the hormone insulin. It helps in regulating the blood sugar level.

(ii) Pituitary secretes growth hormone. It regulates the growth and development of the body.

(iii) The thyroid secretes thyroxine hormone, It regulates carbohydrates, protein and fat metabolism in the body so as to provide the best balance for growth.

1. Thyroxine is the main metabolic hormone in the body. 

2. Thyroxine maintains basal metabolic rate (BMR) by increasing glucose oxidation. It brings about calorigenic effect by energy production. 

3. It also controls normal protein synthesis. 

4. The physical growth, development of gonads and development of mental faculties is under the control of thyroxine. 

5. It controls tissue differentiation during metamorphosis particularly in amphibia. 

6. Body weight, respiration rate, heart rate, blood pressure, temperature, digestion, etc. is regulated by thyroxine.

7. Another hormone of thyroid, i.e. calcitonin regulates calcium metabolism of the body.

Hormones are the chemical messengers which are directly secreted into blood by ductless glands also known as endocrine gland and act on different distant organs.

Thyroxine is the hormone secreted by the thyroid gland. This hormone regulates the metabolism of carbohydrates, fats and proteins. By regulating the metabolism it provides best balanced growth to the body.

Iodine is necessary for the thyroid gland to make thyroxin hormone.

Junction between two neurons from where impulse is transmitted from one neuron to the other neuron is called synapse. All other options are wrong in context to junction between two neurons.

Therefore, correct option is (d).

The answer is (d) nervous and endocrine systems

• Reproductive, respiratory and digestive systems have no role to play in control and regulation of life processes. 
• It is the nervous system and the endocrine system that control and regulates all the processes including Reproductive, respiratory and digestive systems.

A plant hormone that promotes growth is Gibberellin and the hormone that inhibits growth is abscisic acid.

Plant hormone that promotes growth is auxin. It is synthesized at the tip of the plant stem.

Plant hormone that promotes growth is Auxin.

Light falls on one side of the plant, auxins diffuse towards shady side of the shoot.

Auxin stimulates the cell to grow longer on the shady side.

Plant appears to bend towards light.

The hormone secreted by the thyroid gland is thyroxine. It regulates carbohydrate, protein and fat metabolism in the body so as to provide the best balance for growth.

The answer is (d) synapse

• A synapse is a structure that allows a neuron to pass an electric signal to the next neuron or effector cell. 
• Hence it is a junction between two neurons.

Auxin is given in an increased dose which promotes the development of seedless fruits. Other functions of auxin are: it is responsible for elongation of cells at the shoot tip and also is responsible for showing positive phototropism.

At puberty (10 to 12 years of age).

Iodine halogen element is necessary for the making of thyroxine hormone by the thyroid gland.

Adrenaline is the hormone secreted by adrenal glands.

Following are its functions:

 • It acts on heart and due to this heart starts beating faster. Due to this fast beating more blood is supplied to muscles and ultimately they get more oxygen. 

• The blood supply is diverted from digestive system and skin due to contraction of muscles around these small arteries.

 • Breathing rate is also increased due to contraction of diaphragm and ribs.

All these functions then contribute to fight a person with difficult situations and to deal with them.

(i) In this case adrenaline hormone will be highest in the blood. It is produced by the adrenal gland.

(ii) Supply of blood to digestive system and skin is reduced, supply of oxygen increased towards the muscles and also the blood supply to the heart is increased.

Yes feedback mechanism is a very important aspect of hormonal co-ordination as it is responsible for making sure that the desired amount of hormones is released. Also, it makes sure that the timing and amount of the hormones are correct. For example in the sugar level increases in the blood, insulin is secreted which decreases the amount of sugar in the blood. As the amount of sugar falls, insulin also gets reduced.

Menarche comes earlier in the life of a woman.

(a) (i) It is known as menstruation in scientific terms. 

(ii) It is known as periods in everyday language. 

(b) The process of menstruation begins at Puberty. 

(c) The onset of menstruation in human female signify that the reproductive system of human female has started working. 

(d) In the beginning of pregnancy, the process of menstruation stops temporarily but starts again. 

(e) When menstruation stops permanently, it is termed menopause.

Women has a shorter reproductive phase of life.

1. The first occurrence of menstruation at puberty is called menarche. 

2. The permanent stoppage of menstruation is termed menopause. It occurs at 45 to 50 years of age.

At 45 to 50 years of age.

If these glands do not secrete adrenaline then our body won’t get prepared for stressful situations. Also, there are many disorders like Addison’s disorder which a person might have to face such disorders.