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(b) God’s will 

The process of fertilization that takes place inside the body of females is called Internal Fertilization. 

E.g : 

Animals, Human beings.

Fertilization that takes place outside the female body is called External Fertilization. 

E.g. Fish, frogs, Starfish, etc.

Fertilization that takes place inside the body of the female is called Internal fertilization.

E.g.: Human beings, animals.

(a)1. Ovary

2. Fallopian tube (Oviduct)

3. Uterus (Inner lining or Muscular wall)

4. Vagina

(b) Fertilisation occurs in the upper part of the oviduct. Sperm fuses withthe egg and zygote is formed this is called fertilisation.

Fertilization: The fusion of male (sperm) and female (ova) gamete is called fertlization. As the male performs sexual act with the female and as a result of it the semen is deposited in the vagina of the female. Thus the semen has millions of sperms. Only a few of these sperms are able to reach the upper part of the oviduct. If there is an egg in the oviduct it is fertilized by the sperm. As sperm enters the egg and this leads to the formation of zygote, this act is called fertilisation. 

During fusion only the head part of the sperm, which has nucleus, enters the egg. The tail is left behind. The nucleus of the sperm and egg fuse and form the zygote. Soon this zygote becomes many called embryo and reaches the uterus and implants on the wall of the uterus and forms the foetus. Baby develops with in the gestation period of 280 days. After this the baby is delivered.

Fertilization involves the fusion of the male and the female gamete. The male and the female gametes are released from the male and the female reproductive organs. Sperms or male gametes are released from the male reproductive organ i.e., the penis. These sperms then enter the female body through the vagina. Then, they travel through the fallopian tubes where they meet the eggs. Hence, the process of fertilization takes place in the fallopian tubes. During fertilization, the haploid nucleus of the sperm and that of the ovum fuse with each other to form the zygote. This zygote divides to form an embryo which in turn develops into a foetus.

D) Both A and B

Explanations:

•  Leaves with differentiation of mesophyll into palisade parenchyma and spongy parenchyma are termed as bifacial/dorsiventral leaves. Both, Eucalyptus and Nerium has dorsiventral-bifacial leaves characterized by the presence of one to four layers of elongated closely packed palisade parenchyma under lower and upper epidermis.
•  Eucalyptus has isobilateral leaves in which palisade parenchyma is present on both   sides of the spongy tissue.

A) Scattered

Explanations:

1. In monocots, xylem and phloem are organized in vascular bundles scattered throughout the stem.

2. Monocot stems in general possess a simpler arrangement than that found indicots.

The main elements of the stem are merely the vascular bundles and the pith (used for nutrient storage) that surrounds them.

Explanations:

B) Young root

• The thick waxy layer covers the surface of aerial organs is called Cuticle. It is made up of waxy substance called cutin.
•   It is thin in Mesophytes and highly thick in xerophytes. It is absent in hydrophytes and underground organs.

Correct option is (a) Neurons

Electron gain enthalpy of sulphur is more than oxygen due to small size of oxygen. Extra added electron in oxygen has more inter electronic repulsion than sulphur which has large size.

Carbon cannot reduce oxides of sodium or magnesium because carbon is less reactive than magnesium or sodium. Carbon, which is a non-metal, is more reactive than zinc and can be placed just above Zn in the reactivity series. Hence, carbon can reduce the oxides of zinc and all other metals below zinc to form metals.

(a) Zinc

(b) Sodium

(c) Manganese

(d) Mercury

(a) Aluminium can be used a reducing agent other than carbon.

(b) We cannot use an aqueous solution of sodium chloride to obtain sodium metal because if we electrolyse an aqueous solution of sodium chloride, then as soon as sodium metal is produced at cathode, it will react with water present in the aqueous solution to form sodium hydroxide. Hence, electrolysis of an aqueous solution of sodium chloride will produce sodium hydroxide and not sodium metal.

(i) Because iron being more reactive displaces copper from copper sulphate solution by itself and form green coloured ferrous sulphate.

(ii) Qualities exhibited by Mohan are-scientific knowledge, awareness, helpfulness etc.

Many of the metallic oxides react with the hydrogen to form respective hydrides and hence hydrogen is not widely used as reducing agent in metallurgy. 

So the correct answer is d.

(i) Because iron being more reactive displaces copper from copper sulphate solution by itself and form green coloured ferrous sulphate.

(ii) Qualities exhibited by Mohan pre-scientific knowledge, awareness, helpfulness etc.

(i) We should always purchase the gold jewellery from a branded shop with proper receipt and hall marked certificate.

(ii) Government insists on purchasing hall marked jewellery as it contains the gold and its alloyed metal (i.e., copper or silver) in a fixed ratio. 

Associated Value: They will be more careful and educated and thus can't be fooled easily while shopping jewellery and other products

(i) Anklets turned black due to the reaction of silver with atmospheric H₂S, which results in the formation of black coloured silver sulphide (Ag₂S).

(ii) Ag₂S dissolves in acids present in tamarind or lemon juice, so the anklets got their lustre back.

(iii) The values exhibited by Rakhi are awareness, helpful, knowledgeable and scientific temperament.

Element which is cheaper than aluminium and can be used for the reduction purposes is carbon. Carbon reacts with metallic oxides to form carbon dioxide and metal is obtained.

(i) Anklets turned black due to the reaction of silver with atmospheric H₂S, which results in the formation of black coloured silver sulphide (Ag₂S).

(ii) AgrS dissolves in acids present in tamarind or lemon juice, so the anklets got their lustre back.

(iii) The values exhibited by Rakhi are awareness/ helpful, knowledgeable and scientific temperament.

Aluminium cannot be prepared from its salt solution because of its highly electropositive nature. It does not get discharged at the cathode. H, gas is liberated at the cathode when a solution of a salt of aluminium is electrolysed.

Values inferred from this passage are scientific temperament, awareness, environmental concern and knowledge.

Aluminium cannot be prepared from its salt solution because of its highly electropositive nature. It does not get discharged at the cathode. H₂ gas is liberated at the cathode when a solution of a salt of aluminium is electrolysed. 

Values inferred from this passage are scientific temperament/ awareness, environmental concern and knowledge.

(a) Aluminium oxide is electrolysed in molten state to obtain aluminium metal. Oxygen gas is evolved during the process.

(b) Sodium chloride is electrolysed in molten state to obtain sodium metal. Chlorine gas is evolved during this process.

(c) Carbon dioxide is produced when calamine ore is calcined.

(d) Sulphur dioxide gas is evolved when cinnabar ore is roasted.

The metals like Na, K, Ca and Mg never found in their free state in nature because of the reason that all of these metals are high-up in the reactivity series. And just because they are so reactive, they are never found in nature as free elements.

Metal B will be nearer to the top of the activity series since it is highly reactive and is hence found in the form of its compounds and not in free state.

(a) Gold and Platinum are found in nature mainly in the free state.

(b) Sodium and Magnesium are always found in combined state.

(c) Iron (III) oxide; Fe ₂ O ₃ is present in haematite ore.

i. Polarity is 5′-3′ ; — AUG GUA AUC CUA— 

ii. DNA-dependent RNA polymerase, catalyses transcription of mRNA. The strand of DNA with polarity acts as the template. The RNA polymerase binds to the promoter site and starts the process of transcription.

(a) The arrangement of metals in a vertical column in the order of decreasing reactivities is called reactivity series. Increasing order of reactivity: Iron < zinc < magnesium < sodium

(b) Though hydrogen is not a metal but it has been placed in the reactivity series of metals due to the fact that like metals, hydrogen also loses electrons and forms positive ions.

(c) Lead is more reactive than hydrogen and copper is less reactive than hydrogen.

(d) Zinc displaces copper from copper sulphate solution and mercury does not displace copper from copper sulphate solution.

(e) Copper displaces silver from silver nitrate solution and gold does not.

i. Degenerate—When some amino acids are coded by more than one amino acids. 

ii. Unambiguous and specific—When one codon codes for only one specific amino acid. 

iii. A particular codon codes for same amino acid in all organisms except in mitochondria and few protozoa.

i. a is AUG and b is UAA/UAG/UGA 

ii. AUG codes for methionine (initiation codon). UAA/UAG/UGA do not code for any amino acid, i.e., stop or terminating codons. 

iii. There are two sites (P-site and A-site) in the large subunit of ribosome, where subsequent amino acids bind to and thus are close enough to form peptide bond by peptidyl transferase enzyme. The ribosome also acts as a catalyst for the formation of peptide bond.

The collection of diverse alleles of all the genes of a crop plant is called germplasm collection. It is of great benefits in plant breeding programmes it offers to the breeders, the entire of genes and alleles and the characteristics which they express. The breeder selects the most favourable characters of a particular gene and manipulates its transfer to a desirable parent.

1. Maize is a wind pollinated plant. The flowers produce large amount of light and non sticky pollen grains which helps in transportation through wind. 

They possess well exposed stamens and large and feathery stigma to easily capture pollen grains. There is a single ovule in an ovary and arranged in compact inflorescence.

Orchid is an insect pollinated plant. It produce large conspicuous flowers, the small flowers are produced in clusters.

The large flowers are colourful, fragrant and rich in nectar. The insects are attracted by colour and fragrance and are often rewarded by nectar and pollen produced by the flower.

2. Flies and beetles.

Presence of a large quantity of nectar, bright colours of petal, fragrance and large flowers attract birds from long distances.

Anemophily (wind pollination).

c. vitamin B₁₂

Tobacco mosaic virus (TMV).

Tobacco mosaic virus.

Methanogens are the group of bacteria found in both the rumen of cattle and sludge of sewage treatment.

Escherichia coli RY 13.

E.coli and Saccharomyces cerevisae

1. Vitamin A deficiency is one of the most common causes of eye problems. 

2. Vitamin E and Zinc deficiency may also cause for eye problems.

Following precautions should be taken while sowing the seeds in the soil: 

1. The seeds should be sown at right depth in the soil suitable for germination. 

2. The seeds should be sown at proper spacing. 

3. The seeds should not be sown in highly wet soil. 

4. The seeds should not be sown in a dry soil.