Explore topic-wise InterviewSolutions in Current Affairs.

It comes from the Greek word ‘hudor’ meaning water.

• The erosion and deposition by the sea waves give rise to coastal landforms. 
• “Sea Arches”, “Sea Cliff’, Cape, Bay and beaches are formed due to the work of the waves.

• When volcano erupts, some part of the lava may not reach the surface and may cool under the surface and become rocks which are called “intrusive landforms”. 
• A part of the lava which pours on the surface of the earth forms the “extrusive landforms”.

Cyton is the cell body of a nerve cell (neuron), containing cytoplasm and the cell organelles.

The most sensitive region of the retina is Yellow spot.

Real, inverted and small in size

Synapse is a place or a gap where two adjoining dendrites or axons meet but never unite, as there is no continuity between the nerve cells. At the synapse, acetylcholine is secreted which prevents back flow of the impulse.

Dendrites are cytoplasmic processes of the cell body of a neuron.

The photoreceptor cells of the retina sensitive to colour are Cones. 

1. Photon

2. Cerebrum

3. Eating

4. Corpus luteum

5. Typing

A point of contact between two neurons is termed Sensory neuron.

Membranous labyrinth

The part of the central nervous system in which the gray matter is located on the outer side and the white matter on the inner side is Brain.

(c) A layer of specialized neuroglia around myelin sheath of nerve fibres.

1. True

2. False, 

Spinal nerves and cranial nerves constitute the peripheral nervous system.

3. False, 

It is a bony box, enclosed brain.

4. False, 

Spinal nerves are 31 pair.

5. True

1. A nerve chain between a receptor and an effector organ is called Reflex arc.

2. Optic nerve is a type Sensory nerve, whereas spinal nerves are mixed nerves.

3. An inability to focus on nearby objects due to loss of elasticity of the lens with age is called Iris.

4. The part of the central nervous system which responds to the reflex action is Spinal cord.

5. Ear is the organ of balance and hearing in the body.

6. Tympanic chamber is filled with Perilymph.

The chemical messenger by which the nerve impulse travels from one neuron to the other is Acetylcholine.

Corpus callosum joins the two cerebral hemispheres in man.

The answer is (b) Leishmania

The junction between two nerve cells is Synapse.

Myopia: The lengthening of the eyeball or the lens is too curved causes this defect.

Hypermetropia: The shortening of the eyeball or flattening of the eye lens causes this defect.

1. True

2. False, 

Myopia is a defect of the eye caused due to the eyeball elongation.

3. False, 

The part of ear associated with balance is the semicircular canal.

4. False, 

Cochlea of the ear is concerned with the sense of hearing.

5. False, 

Deafness is caused due to the rupturing of the eardrum.

(i) 1—Bitter Taste, 

2—Sour Taste, 

3—Salt Taste, 

4—Sweet Taste.

(ii) The receptors for sensations are located in the taste bud covering the tongue surface.

(iii) Person suffering from cold often complain that they cannot taste their food because their gustatory sensations are not operating well.

(a) Cylindrical lens 

(b) Concave lens 

(c) Convex lens

Biconcave lens used for correcting myopia.

1. Xerophthalmia

2. Cretinism

3. Gustatory cells

4. Pinna

5. Tympanum

6. Taste buds

Structure of taste buds: There are four primary tastes-sweet, salty, sour and bitter. The taste receptors are called taste buds. Each taste bud opens on the tongue surface through a taste pore. Each taste buds contains 60-65 spindle-shaped cells, out of which 5-15 are taste receptor cells and others supporting cells. The taste receptor cells produce protoplasmic outgrowths called taste hair. The taste hair project through taste pore and receive the stimulus of taste.

(i) (a) The part numbered 3 is named as occipital lobe of cerebrum, which is the area of vision. If this part is damaged, the person is unable to see.

(b) The part numbered 4 is named as cerebellum, which is responsible for coordinating the muscular activity for body balancing. If this part is damaged, the body balancing during walking and running would be affected.

(ii) Function of part 1: It governs all mental activities (reason, will, memory, intelligence, higher feelings and emotions).

Function of part 2: It controls all voluntary action and is responsible for taste and smell.

Function of part 5: It controls several involuntary activities, such as heartbeat, breathing, peristaltic motion of the alimentary canal, dilation and concentration of blood vessels, etc.

The type of lens used to correct myopia is Concave. 

Sensory papillae

Accommodation of eye

1. Cerebrum

2. Gray matter

3. White matter

4. Mid-brain

5. Cerebellum

6. Spinal cord

7. Medulla oblongata

8. Hypothalamus

9. Pituitary body

(i) 1. Cerebrum,

2. Cerebellum,

3. Medulla oblongata,

4. Spinal cord.

(ii) 1. Grey matter is outside and white matter inside.

4. White matter s outside and gray matter is inside.

(iii) 3. Medulla oblongata controls all involuntary movements of internal organs e.g., breathing movements of lungs, beating of heart.

4. Spinal cord performs reflex action below the neck.

(iv) Corpus callosum.

The parts of the human ear concerned with hearing are Cochlea, ear ossicles and tympanum.

The part of human brain that controls body temperature is Hypothalamus.

(1) Cerebrum

(2) Cerebellum.

Correct option is A) 1, 2

The answer is (D) Sulphur and copper bacteria

Guttation: The exudation of water from plants in a liquid form, by leaves is known as guttation. It takes place when environmental conditions are favourable, so, as to check transpiration, the air is very humid.

Sometimes, water oozes out of the margin of leaves of peepal, tomato, Nasturtium, lawn grass in the morning hours and in the night in the form of minute drops. This is called guttation.
In plants which show guttation, there are special stomata, the water stomata or hydathodes located on margin and the apex of leaves, just next to the vein ending. They open internally into a small cavity surrounded by thin-walled parenchyma.

Conditions for guttation:

(i) Guttation increases when absorption rate is more than the rate of transpiration.

(ii) When there is enough humidity in the atmosphere, then guttation is more.

Mainly three types of pigments are found in plants, namely, chlorophyll, carotenoids and phycobilins. All three pigments are found in chloroplasts. These pigments trap the light energy. Other pigments found in plastids are called chromoplastids. Photosynthesis takes place only in chloroplast. Hence, the pigment outside it such as anthocyanons, yellow xanthophyll and red-orange coloured carotenoids, do not take part in photosynthesis. But carotenoids and phycobilins present in chloroplasts, helping in photosynthesis, indirectly. These absorb light energy and transfer to chlorophyll pigment.

The answer is (D) Human and frog

Guard cells contain chlorophyll and so, carry out photosynthesis. When guard cell swells up, stomata will open and when it contracts, stomata close.

Two functions of flowers related to reproduction are as follows: 

(i) To produce male and female gametes, after developing male and female gametophytes in reproductive organs, respectively. 

(ii) To accomplish the fusion of male and female gametes or fertilisation.

Grafting: In this method of reproduction, two plants of closely related varieties are joined together, so that they live as one plant. The plant, whose roots remain in the soil is called as stock and the one of which small shoot is to be used is called Scion. Cambium of both stock and scion are fused to form a connection between the two. This fusion can be done in various ways. Accordingly, grafting is classified into three types:

(A) Whip or tongue grafting: In this type, stock and Scion, which are of the same diameter are given oblique cuts, so that scion closely fits over the stock. They are tied by moist clay.

(B) Wedge grafting: In this type of grafting, wedge-shaped or V-shaped cut is given in the stock. In the scion, a vertical slit is formed, so that it can be inserted into the stock. Then Scion and stock are tied by the moist clay, as in tongue grafting.

(C) Crown grafting: If the diameter of the stock is more than that of the scion, then more than one scions can be grafted on a single stock. Scion is cut into long wedges on the lower end. These cuts should match with those present in the stock. Later on, these are tied together firmly.

(D) Bud grafting: In this type of grafting, a bud along with some portion of the living tissue is taken as a scion. T-shaped cut is made in the bark of the stock. Scion is then inserted into this T-shaped cut. Both are then tied together, with strings and not allowed to dry. After a few days, bud becomes part of the stock plant and starts germinating.

The ovaries besides producing eggs also secrete two hormones:

(a) Progesterone, and

(b) Estrogen.

These hormones help in the secretion of corpusluteum. If the egg is not fertilised, then corpusluteum of ovary degenerates. Periodically, the quantity of progesterone hormone decreases in the blood, resulting in the bursting of blood vessels and the blood along with uterine fluid comes out. This is called menstruation. This process goes on in a cyclic manner, after every 28 days. It is called the menstrual cycle.

Reflex action is an automatic response to a stimulus which is not under conscious control, e.g., sneezing, blinking of eyes, coughing, etc.

In hydrophytes (aquatic plants), waste product diffuses out from the cell membrane of the cell into the surrounding water.