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(a) Metameres (somites).

The brain of leech lies above, the Pharynx.

Four  pairs.

Blood platelets.

White and yellow fibres. White fibres are thin, wavy, unbranched, inelastic, occur in bundles and formed of protein collagen. Yellow fibres are thick, straight, elastic, branched, occuring singly, formed of protein elastin.

Simple gland is composed of single cell, while compound gland is composed of multiple cells. 

The cells and fibres are loosely arranged in a semi-fluid matrix; in loose connective tissue. The cells and fibres are compactly packed in dense connective tissue. Areolar tissue is an example of loose connective tissue, while tendon and ligament are examples of dense connective tissue.

Fibres and fibroblasts are compactly packed in the dense connective tissues. Orientation of fibres show a regular or irregular pattern and are called dense regular and dense irregular tissues.

In dense regular connective tissues, the collagen fibres are present in rows between many parallel bundles of fibres. Tendons, which attach skeletal muscles to bones and ligaments which attach one bone to another are examples of this tissue. Dense irregular connective tissue has fibroblasts and many fibres that are oriented differently. This tissue is present in the skin. 

Simple gland is composed of single-cell while compound gland is composed of multiple cells.

Adipose tissue : Adipocytes. 

Adipose tissue is an example of loose connective tissue, while blood tissue is a specialized connective tissue. Adipose tissue is usually located beneath the skin. The cells of the adipose tissue are specialized to store fat. Blood facilitates transportation of various materials in the body.

(b) Nervous system

Adipose tissue is a type of loose connective tissue located mainly beneath the skin. The cells of this tissue are specialised to store fats. The excess of nutrients which are not used immediately are converted into fats and are stored in this tissue. Blood is a fluid connective tissue. The main function of blood is to transport gases, nutrients and waste products in the body.

Septal nephridia, present on both sides of intersegmental septa of segment 15 to the last open into intestine. Pharyngeal nephridia, present as three paired tufts in the 4th, 5th and 6th segments.Both are same structurally and functionally.

Setae:-Their principal role is locomotion. They are S-shaped. They are embedded in the epidermal pits in the middle of each segment.

Red Blood Cells and White Blood Cells.

Connective tissue

Cells of cartilage

(a) The cells of cartilage are called chondrocytes.

(b) The tail like portion of the neuron is called axon.

(c) Ciliated epithelium are present in the inner surface of hollow organs; like bronchioles and fallopian tubes.

Respiration by skin is known as cutaneous respiration. Frog and earthworm show that.

Tail like structure of a neuron

(i) Exocrine glands 

• secrete mucus, saliva, oil, milk, digestive enzymes. 

• products released through ducts/tubes.

(ii) Endocrine glands 

• secrete hormones.

• secrete directly into the fluid bathing the gland.

Found in the inner lining of bronchioles. Cilia help trap and clear dust foreign particles.

Epithelial Tissue :

1. Simple epithelium: is composed of a single layer of cells resting on abasement membrane. 

2. Compound epithelium: consists of two or more cell layers and has protective function. Simple: 

• Composed of single layer of cells. 

• Functions as lining for body cavities, ducts and tubes. 

1. Squamous

• single thin layer of flattened cells. 

• found in walls of blood vessels, air sacs of lungs for diffusion. 

2. Cuboidal 

• single layer of cube like cells. 

• found in ducts of glands and tubular parts of nephron for secretion and absorption. 

3. Columnar

• single layer of tall and slender cells. 

• free surface may have microvilli. 

• found in lining of stomach and intestine for secretion and absorption. 

4. Ciliated

• columnar or cuboidal cells with cilia. 

• move particles or mucus in specific direction, in bronchioles, fallopian tubes.

Types of Epithelial Tissue :

1. Simple epithelium: is composed of a single layer of cells resting on abasement membrane. 

2. Compound epithelium: consists of two or more cell layers and has protective function. 

(i) a : epidermal cell 

b : guard cell 

(ii) In dicot plants. 

(iii) The stomatal apparatus includes the stomatal aperture, guard cells and the surrounding subsidiary cells. 

Guard cells.

The problem of DNA doubling can be solved by having a lineage on the cells of specialised organ.  

Explanation: 

The problem of DNA doubling can be solved by having a lineage on the cells of specialised organ which have half the number of chromosomes and half the amount of DNA. when gametes fuse at the time of sexual reproduction,to form a new organism,it results in the re-establishment of the number of chromosomes and DNA content in the new generation

A group of cells which are similar in origin; similar in structure and similar in function are called simple permanent tissue.

Simple permanent tissues are of three types :

(i) Parenchyma: (a) Parenchyma is a simple permanent living tissue which is made up of thin-walled similar isodiametric cells, 

(b) They may be oval, rounded or polygonal in outline, 

(c) The cell wall is made up of cellulose, 

(d) Cells may be closely packed or have small intercellular spaces for exchange of gases. Internally each cell encloses a large central vacuole and a peripheral cytoplasm containing nucleus,

(e) The adjacent parenchyma cells are connected with one another by plasmodesmata. 

(f) The typical parenchyma is meant for the storage of food, slow conduction of various substances and for providing turgidity to the softer parts of the plants.

(ii) Collenchyma : (a) Collenchyma is a simple permanent tissue of refractile non-lignified living cells which possess pecto-cellulose thickenings in specific areas of their walls, 

(b) The cells are often elongated. They are circular, oval or angular in transverse section. Each cell possesses a large central vacuole and a peripheral cytoplasm. Wall possesses uneven longitudinal thickenings in specific areas.

(iii) Sclerenchyma : (a) Sclerenchyma is a simple supportive tissue of highly thick-walled cells with little or no protoplasm, 

(b) The cell cavities are narrow. The thickening of the wall is made up of cellulose or lignin or both, 

(c) Sclerenchyma is of two types- Sclerenchyma fibres and Sclereids.

(i) Sclerenchyma fibres : The sclerenchyma fibres are highly elongated, narrow and spindle-shaped thick-walled cells with pointed or oblique end walls. The adjacent fibres possess simple oblique pits. Sclerenchyma fibres constitute the major mechanical tissue of the plants because they can bear compression, pull, bending and shearing.

(ii) Sclereids : They are highly thickened dead sclerenchyma cells with very narrow cavities. Sclereids are broader as compared to the fibres being isodiametric polyhedral, short or cylindrical.

In radian vascular bundles, xylem and phloem are arranged separately in different radii. Radial bundles are found in roots of monocots and dicots.

(i) Radial bundles : Xylem and phloem occur on different radii.

(ii) Conjoint bundles : Xylem and phloem are situated at the same radius of vascular bundle.

• Collateral bundles
• Bicolateral bundles
• Concentric bundles

The correct option is (B)

Given that

Charge (Q) = 1 C

Electron (e) = 1.6 x 10^-19

Number of electron (n) = ?

Q = ne

1 C = n x 1.6 x 10^-19 C

n = 1/(1.6 x 10^-19)

n = 6.25 x 10¹⁸ electron

Tissue System :

1. Epidermal tissue system : It includes cuticle, epidermis, epidermal hairs, root hairs, trichomes and stomata. 

2. The ground tissue system : It is made up of parenchyma, collenchyma, sclerenchyma. In dicot stems and roots the ground tissue is divided into hypodermis cortex, endodermis, pericycle, medullary rays and pith. 

3. The vascular tissue system : It includes vascular bundles which are made up of xylem and phloem.

Using the formula  \(t=\frac{nV}{500A'}\) , 

we can find the size of the liquid molecule, 

where V = Volume of liquid (say oleic acid), 

n = No. of drops in the sol. Of \(\frac{1}{500}\) concentration. 

A = Area of the film of oleic acid left. 

t = Thickness of the film.

A = πr² = 3.142 × 3.458² = 37.57 cm² 

Types of Permanent Tissue :

(i) Simple Tissue

(a) Parenchyma : Thin walled cells, with intercellular spaces, cell wall is made up of cellulose. It performs the function like photosynthesis, storage, secretion.

(b) Collenchyma :  It is formed of living, closely packed isodimetric cells. It’s cells are thickened at the corners due to deposition of cellulose and pectin. It provides mechanic support to the growing parts of the plant.

(c) Sclerenchyma : It is formed of dead cells with thick and lignified walls. They have two types of cells : fibres and sclereids.

(ii) Complex Tissue

(a) Xylem : Xylem consists of tracheids, vessels, xylem fibres and xylem parenchyma. It conducts water and minerals from roots to other parts of plant.

Protoxylem : The first formed primary xylem elements.

Metaxylem : The later formed primary xylem.

Endarch : Protoxylem lies towards the centre and metaxylem towards the periphery of the organ.

(b) Phloem : Phloem consists of sieve tube elements, companion cells, phloem fibres and phloem parenchyma. Phloem transports the food material from leaves to various parts of the plant. 

Protophloem : First formed phloem with narrow sieve tubes. 

Metaxylem : Later formed phloem with bigger sieve tubes.

(b) Sclerenchyma : photosynthesis, storage and secretion is not a matching pair. The function of sclerenchyma is to provide mechanical support to organs.

r = 11.24 cm

Surface area

= 4 πr²

= 4 × 3.142 × (11.24)² = 1588 cm²

Meristematic tissues are composed of cells that have the capability to divide. These cells are exist in different shapes without intercellular space. Cells are thin walled, rich in protoplasm, without vacuoles. 

Permanent tissues are derived from meristematic tissue and are composed of cells have their definite shape, size and function. These cells may be thin walled (living) or thick walled (dead).

No, significant figures do not depend on the system of units, e.g., 25 g has two significant digits and 2.5 × 10^-2 kg also has two significant digits.

His sister had given him letters of introduction to people living there as he did not know anyone there. She knew that he would not speak to anybody and his nerves would be worse from moping. 

That is why she had given him letters of introduction to all the people she knew there.

Mrs. Sappleton said that she hoped Framton did not mind the open window. She told him that her husband and her brothers would be coming home directly from their shooting, and they always came that way.

The niece told Nuttel that about three years ago Mrs. Sappleton's husband and her two younger brothers had gone for their day's shooting through the open French window. They never came back. In crossing the moor to their favourite shooting spot, they were all engulfed in a piece of bog. It was a wet summer and places that were safe in other years gave way suddenly without warning. Their bodies were never recovered.

When Framton turned around, he saw a silhouette of three men and dog in the evening light. Then a hoarse voice was heard shouting at the dog. The description matched exactly with that of Vera's description.

While explaining the mystery behind the open French window, the events narrated by Mrs. Sappleton's niece manage to create a sense of foreboding. Later, when the three men approach the open window, the reader (like Framton) can only logically conclude that they were ghosts. Hence, one can say that this story does contain elements of the mystery.

The girl said that the spaniel was the reason for his lightning exit. She said that he had a horror of dogs. She explained that he was once hunted into a cemetery somewhere on the banks of the Ganges by a pack of pariah dogs. He had to spend the night in a newly dug grave, with the creatures snarling, grinning and foaming just above him.

Framton Nuttel was suffering from nervous breakdown. The doctor had advised him to stay away from the city life So he had come to the “rural retreat” to undergo a nerve cure in the peaceful environment .