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DNA is considered a better hereditary material than RNA because of the following reasons: 

i. It is able to generate its replica (replication). 

ii. It is chemically and structurally stable. 

iii. It provides the scope for slow changes (mutation) that are required for evolution. 

iv. It expresses itself in the form of Mendelian characters through RNA.

Packaging of DNA in eukaryotes 

• The proteins associated with DNA are of two types—basic proteins (histone and protamine) and acidic non-histone chromosomal (NHC) proteins. 

• The negatively charged DNA molecule wraps around the positively charged histone proteins to form a structure called nucleosome. 

• The nucleosome core is made up of four types of histone proteins—H₂A, H₂B, H₃ and H₄— occurring in pairs. 

• 200 bp of DNA helix wrap around the nucleosome by 1¾ turns, plugged by H₁ histone protein.

According to Chargaff's rule

\(\frac{A}{G}\) = \(\frac{T}{G}\) = 1

G = G, G = 410, hence C = 410

G + C = 410 + 410 = 820

So, A + T = 1500 - 820 = 680

A = T, so T = \(\frac{680}{2}\) = 340

So, pyrimidines = C + T

= 410 + 340 = 750

DNA ligase joins or seals the discontinuous DNA fragments.

Bee-keeping : It is the practice of keeping, caring & management of honeybees on a large scale for obtaining honey and wax. 

Many farmers use bee-keeping for additional small income. Also, there are big farms called apiaries/bee farms.

1. -e 

2. -b 

3. -d 

4. -a

5. -c

Water vascular system, tube feet.

1. phylum coelenterata. 

2. Phylum Annelida / Phylum Platyhelminthes .

1. The umbilical cord connects Foetus and placna.

2. The process of releasing of egg from the ovary is called Ovulation.

3. A hormone secreted in a female to facilitate parturition is Oxytocin.

4. Placenta is Selectively permeable.

5. One egg is normally released from ovary in the human females after 28 Days.

There is smoke in the towns because there are buses and motors and trams, plying often.

b) There are no players in villages.

The town child loves the sky which is far above.

The town child wants to live in a country.

1. Human gestation period is about 280 days.

2. The expulsion of the foetus from the body to the mother in a human female is called Parturition.

3. The female equivalent of penis is the Clitoris.

4. The embryo inside the uterus is protected from jerks or mechanical shocks by Amniotic fluid.

The lanes in the country are so quiet because they are not crowded with traffic and feet.

(c). 280 days.

The connective tissue surrounding the ovary is Mesovarium.

(a) Amniotic fluid

(b) Uterus

(c) Amniotic membrane

(d) Inguinal canal

Lateral phase in the menstrual cycle in which the remnant of follicle in the ovary turns to corpus luteum.

The fluid surrounding the developing embryo is Amniotic fluid.

Auditory nerve transmits messages from the ear to the brain.

Controlled grazing is a simple method of soil conservation, It is to restrict the grazing of cattle, sheep and goats on grasslands and within forests. When cattle graze on fields, grass and smaller plants get tom from their roots, leaving the soil loose and exposed to wind and water erosion. Moreover, the pressure of the animals hooves on the soil makes it lose its cohesion and structure, exposing it to the forces of wind and water. Land meant for grazing of cattle should be specially selected and fenced off.

Gradation is the process of levelling the land by means of moving agents like rivers, or wearing  away and lowlands are raised by adding the eroded material by the process of deposition. This is because there id constant earth movement which raises mountains and winds, seas and waves. The highlands are made low by erosion and theis process is called degradation and materials are deposited elsewhere in depressions like valleys,lakes etc, and etc and these lowlands are raised by the process called aggradation

When the surface layers of rounded rocks  and boulders gradually peel off in layers is called exfoliation. This occurs due to expansion of the outer layer during the day and the contraction of the same layer during the night, repeatedly over a period of time.

Hydration : This occurs when water itself chemically combines with some minerals present in rocks. Thus, crystalline minerals, such as feldspar and potash, absorb water and become a powdery mass due to the process of hydration, resulting in their erosion. 

Solution : This is the simplest form of chemical weathering by which some minerals dissolve in water when rainwater falls on rocks or when river water flows over rocks. The soluble minerals dissolve and are removed, . resulting in the breakup of the rocks.

Granular disintegration : A form of weathering where the grains of a rock become loosened and fall out to leave a pitted and uneven surface. 

Exfoliation : When the surface layers of rounded and boulders gradually peel off in layers due to expansion of the outer layer during the day and the contraction of the same layer during night, the process is called exfoliation.

The various methods of conserving soil are : 

Contour tilling, terrace farming, strip cropping, contour bunding, afforestation, crop rotation, fallowing and controlled grazing.

We can reduce soil degradation by Contour tilling, terrace farming, strip cropping, contour bunding, afforestation, crop rotation, fallowing and controlled grazing.

Soil formation is an important for mankindas :

1. A habitat for several plants and animals 

2. A storage bank for water and nutrients 

3. Foundation of the world’s food chain 

4. Provides an anchor for plants

During preparation of idlis, rice and black gram flour is fermented by air borne Leuconostoc and Streptococcus bacteria. CO produced during fermentation makes them puffy.

Graham  Bell

Jawaharlal Nehru Port

The roads connecting the tehsils, main towns and industrial areas to district headquarter and to each other are called district roads.

Kandla  Port

Mumbai Port.

Public Private Partnership

The branch of HBJ pipeline is situated in Kota city of Rajasthan.

NH 11 is the most important highway in Rajasthan from point of security.

NH 8 is the most important and busiest highway passing through Rajasthan.

Rajasthan Road Vision 2025 has been prepared to transform the road network in Rajasthan. The PWD prepared a long term vision for development of roads in the initial twenty five years of the 21st century. This vision gives importance to construction, maintenance and quality of roads. Under this vision stress was given on connecting all villages during the initial 15 years followed by construction of expressways, flyovers and four-lane roads. This vision considered it necessary to connect important places of religious importance, tourism, mining and industries with new roads. Rajasthan can be considered as a ‘Model State’ in road network.

The manipulation of living organisms by the human race cannot go on any further, without regulation. Some ethical standards are required to evaluate the morality of all human activities that might help or harm living organisms. Going beyond the morality of such issues, the biological significance of such things is also important. Genetic modification of organisms can have unpredictable results when such organisms are introduced into the ecosystem.

The answer is (b) Bacillus thermogenesis

1. Culture medium: The nutrient medium, the chemical composition of which is precisely known and which is used to raise tissue culture and its multiplication is known as culture medium. 

2. Protoplast: The contents of the plant cell devoid by the cell wall collectively constitute the protoplast. Protoplast is thus a plant cell without a cell wall. 

3. Explant: The part of the plant used for raising tissue-culture is known as explant. Meristematic tissue, part of root, stem or leaves and flower and floral parts can be used as explant. 

4. Transgenic plant: Genetically modified plants are known as transgenic plants. Transgenic plants are developed by introducing desired features through recombinant DNA technique through genetic engineering

Culture of a mature or immature embryo of plants is called embryo culture. Embryo culture is used to induce germination of the mature embryo and for development of an immature embryo. When an embryo develops from somatic cells, it is called the somatic embryo. 

It can be haploid or diploid depending upon the somatic cells from which it develops. The normal embryo is formed from the zygote. This is diploid and is formed by the fusion of male and female gametes

Several important crop plants are attacked by a variety of insects and pests. Bacillus thermogenesis bacterium is known as Bt in short. It was discovered that this was instrumental in causing the death of larvae of four species of Bollworm. This bacterium was registered as a biopesticide in the U.S.A. in 1961. A gene called a cry gene is found in this bacterium. This gene (cry gene) codes for a protein which kills the insect pests. This gene was separated from Bt bacterium and was incorporated in the genome of the cotton plant. The cotton variety so developed is called Bt cotton or killer cotton. This cotton is resistant to the Bollworm.

The artificial seed contains, the embryo and shoot bud, nutrients, plant hormones, pesticide and antibiotic substances.

The regeneration of plants through tissue culture technique is called micropropagation. In this technique, plantlets are developed through differentiation in the callus and these plantlets are transferred to nature after hardening and acclimatization. 

This technique has been adopted to regenerate commercially important plants such as many species of orchids (Cattleya, Cymbidium, Dendrobium, Vanda) and many ornamental plants such as “Gerbera”, Carnation, Bignonia, Chrysanthemum, etc. Many institutions and universities are engaged in a multiplication of important forestry and horticultural plants by micropropagation.