Haemolymph.

ENIAC- A computer had approximately 18,000 vacuum tubes. The size occupied by the ENIAC could be equivalent to a class room. ENIAC, which was used by the American Military in 1946 to predict the traj ectory of artillery shells, recognized as the world's first general purpose computer.

Air is a mixture, because samples from different places give different percentage of its components.

When a ray of light travels from rarer medium to the denser medium it bent towards the normal.

28 Electrons.

Full form of SI system is "International system of units"

Operating system is a software that makes the hardware devices process the data fed by the user and to display the result on the output devices, like monitor.
Without the operating system, computer can not function on its own. Some of the popular operating system are Iinux, windows, Mac, Android etc.,

Heat capacity of ball = 50 J⁰C^-1
Heat lost Q = 2000 J
Fall in temperature t = ?
Heat capacity = \(\frac { Q }{ t } \)
50 = \(\frac { 2000 }{ t } \)
t = \(\frac { 2000 }{ 50 } \)
t = 40⁰C

Ohm's law states that electric potential difference across two points in an electrical circuit is directly proportional to the current passing through it that is
V ∝ I
The proportionality constant is the resistance (R) offered between two points. Hence Ohms law is written as
V = RI (or) V = IR

The number which designate and distinguish various atomic orbitals and electrons present in an atom are called quantum numbers.

(a) It is a non-uniform motion
(b) 20 cm
(c) Velocity = \(\frac { Displacement }{ time\ taken } \)
=\(\frac { Total\ distance }{ time\ taken } \)
=\(\frac { 20\times 10^{ -2 } }{ 2.5 } \)
= \(\frac { 2 }{ 2.5 } \) = 0.08 m/s (or) cm/s.

Aquatic habits of amphibians:
1. The larva of amphibians (tadpole) lives in water and breathes with gills.
2. External fertilization occurs in frog with water as a medium of fertilization.
3. The adult frog has webbed feet to swim in water
4. The skin is moist and glandular which helps in Respiration.
Terrestial habits of amphibians:
1. The adult live on land and breathe through lungs. Bucco-Pharynx also helps in respiration.
2. The fore limbs are short and help to hop on land.

A ray of light going towards the centre of curvature is reflected back along the same path. It is a rule for construction of image formed by spherical mirrors.

The measuring unit of the thickness of a plastic carry bag is micron.

(a) Photonasty phenomenon is shown by the flowers of plant A and B.
(b) A- Taraxacum officinale (common dandelian). B- Ipomea alba (moon flower).
(c) Seismonasty or thigmonasty is exhibited by the leaves of plant C.
(d) Mimosa pudica leaves behave like those of plant C.

The adolescent girl affected by Anaemia blood contain Haemoglobin is very low because she takes very less amount of micro-nutrients like iron. So doctor advised to her to take leafy vegetables and dates. It contain large amount of Iron.

1. They provide water to growing crops, without waiting for rainfall.
2. They provide water for irrigation even when there is no rain.
3. They reduce soil erosion.
4. They recharge ground water.
5. They improve drainage.
6. The excavated soil can be used to enrich soil in fields and ·Ievelling lands.
7. They promote fish rearing.
8. They provide water for domestic purposes and livestock.

1. The instrument used to measure the purity of milk is Lactometer .
2. Lactometer works on the principle of gravity of milk.
Working:
1. The lactometer consists of a long graduated test tube with a cylindrical bulb with the graduation ranging from 15 at the top to 45 at the bottom. The test tube is filled with air. This air chamber causes the instrument to float.
2. The spherical bulb is filled with mercury to cause the lactometer to sink up to the proper level and to float in an upright position in the milk.
3. Inside the lactometer there may be a thermometer extending from the bulb up into the upper part of the test tube where the scale is located.
4. The correct lactometer reading is obtained only at the temperature of 60^oC.
5. A lactometer measures the cream content of milk. More the cream, lower the lactometer floats in the milk. The average reading of normal milk is 32.
6. Lactometers are used highly at milk processing units and at the dairies.

In one such disease, there is a progressive decrease in WBC of the patient.
a) Name the disease and its causative agent.
Name of the disease : AIDS
Causative agent :. HIV - Human immuno deficiency virus
b) Name the type of WBC affected during infection.
Type of WBC affected by HIV : T-Iymphocytes
c) How does the blood of a patient come in contact with blood of healthy patient?
Mode of Transmission : Sexual contact, transfusion of unscreened blood, by surgical equipments from infected mother to the foetus.
d) Suggest three methods that help in preventing such infection.
Prevention :
1. Disposable syringes and needles should be used .
2. Protected and safe sexual contact.
3. Screening of blood before blood transfusion .
4. Avoid sharing shaving blades/razors.

Simple Epithelium:
1. It is formed of single layer of cells. It forms a lining for the body cavities and ducts.
2. On the basis of structural modification of the cells, simple epithelium is further divided into following types.
(i) Squamous epithelium
(ii) Cuboidal epithelium
(iii) Columnar epithelium
(iv) Ciliated epithelium
(v) Glandular epithelium
(i) Squamous epithelium

1. It is made up of thin, flat cells with prominent nuclei. These cells have irregular boundaries and bind with neighbouring cells
2. The squamous epithelium is also known as pavement membrane, which form delicate lining of the buccal cavity, alveoli of lungs, proximal tubule of kidneys, blood vessels etc
3. It protects the body from mechanical injury, drying and invasion of germs
4. It also helps in filtration by forming a selectively permeable merm surface.
(ii) Cuboidal epithelium

1. It is composed of single layer of cubical cells.
2. The nucleus is round and lies in the centre.
3. This tissue is present in the thyroid vesicles, salivary glands, sweat glands, exocrine pancreas etc.
4. Their main function is secretion and absorption.
(iii) Columnar epithelium

1. It is composed of a single layer of slender, elongated and pillar like cells.
2. Their nuclei are located at the base.
3. It is found lining the stomach, gall bladder, bile duct, small intestine, colon, oviducts etc.,
4. They are mainly involved in secretion and absorption.
(iv) Ciliated epithelium

1. Certain columnar cells bear numerous delicate hair like out growths called cilia and are called ciliated epithelium.
2. Their function is to move particles or mucus in a specific direction over the epithelium.
3. It is seen in the trachea of wind-pipe, bronchioles of respiratory tract, kidney tubules and fallopian tubes of oviducts.
(v) Glandular epithelium

1. Epithelial cells are often modified to form specialized gland cells which secrete chemical substances at the epithelial surface.
2. Sometimes a portion of the epithelial tissue folds inward to form a multicellular gland, which lines the gastric glands, pancreatic tubules and intestinal gland

Alimentary canal of man:
Alimentary canal is a muscular coiled, tubular structure. It consists of mouth, buccal cavity, pharynx, oesophagus, stomach, small intestine (consisting of duodenum, jejunum and ileum), large intestine (consisting of caecum, colon and rectum) and anus.
Mouth: The mouth leads into the buccal cavity. The buccal cavity is a large space bound above by the palate (which separates the wind pipe and food tube), below by the throat and on the sides by the jaws. The jaws bear teeth.
Teeth: Teeth are hard structures meant for holding, cutting, grinding and crushing the food. In human beings two sets of teeth (Diphyodont) are developed in their life time.
Each tooth has a root fitted in the gum (Theocodont). Permanent teeth are of four types (Heterodont), according to their structure and function namely incisors, canines, premolars and molars.
Dental formula represents the number of different type of teeth present in each half of a jaw (upper and lower jaw).
For Permanent teeth in each half of upper and lower jaw:
\(\cfrac { 2,1,2,3 }{ 2,1,2,3 } =16\times 2=32\)
Salivary glands: Three pairs of salivary glands are present in the mouth cavity. They are: parotid glands, sublingual glands and submaxillary or submandibular glands
i. Parotid glands are the largest salivary glands, which lie in the cheeks
ii. Sublingual glands are the smallest glands and lie beneath the tongue.
iii. Submaxillary or Submandibular glands lie at the angles of the lower Jaw.
Tongue: The tongue is a muscular, sensory organ which helps in mixing the food with the saliva.
Pharynx: The pharynx is a membrane lined cavity behind the nose and mouth, connecting them to the oesophagus. It serves as a pathway for the movement of food from mouth to oesophagus.
Oesophagus: Oesophagus or the food pipe is a muscular-membranous canal about 22 cm length. It conducts food from pharynx to the stomach by peristalsis (wave-like movement) produced by the rhythmic contraction and relaxation of the muscular walls of alimentary canal.
Stomach: The stomach is a wide J-shaped muscular organ located between oesophagus and the small intestine
Small intestine: The small intestine is the longest part of the alimentary canal, which is a long coiled tube measuring about 5 - 7 m. It comprises three parts duodenum, jejunum and ileum.
1. Duodenum is C-shaped and receives the bile duct (from liver) and pancreatic duct (from pancreas).
2. Jejunum is the middle part of the small intestine. It is a short region of the small intestine.
3. Ileum forms the lower part of the small intestine and opens into the large intestine. Ileum is the longest part of the small intestine. It contains minute finger like projections called villi (one millimeter in length) where absorption of food takes place. Internally, each villus contains fine blood capillaries and lacteal tubes. The small intestine serves both for digestion and absorption. It receives (i) the bile from liver and (ii) the pancreatic juice from pancreas in the duodenum.
Liver: It is the largest digestive gland of the body which is reddish brown in colour. Bile salts help in the digestion of fats by bringing about their emulsification (conversion of large fat droplets into small ones).
Pancreas: It is a lobed, leaf shaped gland situated between the stomach and duodenum. Pancreas acts both as an exocrine gland and as an endocrine gland.
Large intestine: The unabsorbed and undigested food is passed into the large intestine. It extends from the ileum to the anus. It is about 1.5 meters in length. It has three parts- caecum, colon and rectum . 
The caecum is a small blind pouch like structure situated at the junction of the small and large intestine. From its blind end a finger - like structure called vermiform appendix arises. It is a vestigeal (functionless) organ in human beings
The colon is much broader than ileum. It passes up the abdomen on the right (ascending colon), crosses to the left just below the stomach (transverse colon) and down on the left side (descending colon).
The rectum is the last part which opens into the anus. It is kept closed by a ring of muscles called anal sphincter which opens when passing stools.

Features of modern periodic table:
(i) All the elements are arranged in the increasing order of their atomic number.
(ii) The horizontal rows are called periods. There are seven periods in the periodic table.
(iii) The elements are placed in periods based on the number of shells in their atoms.
(iv) Vertical columns in the periodic table starting from top to bottom are called groups. There are 18 groups in the periodic table.
(v) Based on the physical and chemical properties of elements, they are grouped into various families.