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The primary sex organ in human male is testis

‘A’ is promoter sequence of DNA. 

‘B’ is coding strand.

Transcription is defined as the process of copying of genetic information from template strand of DNA into a complementary single stranded RNA transcript.

(b) only (ii)

Correct Answer is: (D) Detritivores

There are many examples of detritivores; some of them include millipedes, dung beetles, earthworms, fiddler crabs and sea cucumbers. Earthworms eat decaying plant and animal matter in the soil.

Correct Answer is: (A) Complementary & antiparalled 

The DNA double helix is anti-parallel, which means that the 5' end of one strand is paired with the 3' end of its complementary strand (and vice versa). 

Nucleotides are linked to each other by their phosphate groups, which bind the 3' end of one sugar to the 5' end of the next sugar.

(D) Ribonucleoside + Phosphate group

(B) Paleontology

Post-mating or post zygotic isolating mechanisms are:

i. Gamete mortality: Sperm transfer takes place but egg is not fertilized.

ii. Zygote mortality: Egg is fertilized but zygote dies.

iii. Hybrid sterility: Hybrids are sterile.

Process of evolution is supported by evidences provided by various branches of biology. They are:

i. Palaeontology

ii. Comparative Anatomy

iii. Embryology

iv. Genetics

Correct Answer is: (C) Amniocentesis 

Amniocentesis (also referred to as an amniotic fluid test or, informally, an "amnio") is a medical procedure used primarily in prenatal diagnosis of chromosomal abnormalities and fetal infections as well as for sex determination.

(C) Amniocentesis

Correct option is (c) Non-programmed decision

(i). Efflorescence is the formation of powdery deposit on the surface of rock as a result of loss of moisture or water on exposure to air. 

(ii). Efflorescence is the formation of whitish powdery deposit on the surface of rocks like gypsum in dry regions. It is formed as mineral rich water, rises to the surface through capillary action and then evaporates.

(iii). Gypsum crystals are sometimes found to occur in the form that resembles the petals of flower. This happens mostly in arid areas or desert terrains, where there is rapid loss of water. This phenomenon is called as efflorescence.

When gypsum is added to cement by mixing with an adequate quantity of water, it forms a plastic mass that gets into a hard solid in 5 to 10 minutes.

(i). The strength of metallic bond in alkaline earth metals is higher than alkali metals due to the presence of 2 electrons in its outermost shell as compared to alkali metals, which have only 1 electron in valence shell.

Therefore, alkaline earth metals are harder than alkali metals.

(ii). The alkaline earth metals have greater nuclear charge and more valence electrons, thus metallic bonding is more effective. Due to this they are harder than alkali metals.

When Plaster of Paris is heated above 393K, no water of crystallisation is left and anhydrous calcium sulphate (CaSO₄) is formed. This is known as ‘dead burnt plaster’.

Answer is Humans

Alkali and alkaline metals are good reducing agents, they cannot be obtained by chemical reduction.

When the alkali metal is dissolved in liquid ammonia, a deep blue coloured solution is formed. 

M +(x +y)NH₃= [M(NH₃ )_x ]⁺ + [e (NH₃ )y ]^-

The ammoniated electrons absorb energy corresponding to red region of visible light. Therefore, the transmitted light is deep blue in colour.

Clusters of metal ions are formed at higher concentration (3M) which causes the solution to attain a copper-bronze colour and a metallic lustre.

Potassium and caesium have much lower ionization enthalpy than that of lithium. As a result, these metals on exposure to light, easily emit electrons but lithium does not. Therefore, K and Cs rather than Li are used in photoelectric cells.

Let the oxidation state of Na be y.

In case of peroxides, the oxidation state of oxygen is -1.

2(y) + 2(-1) = 0

2y – 2 = 0

2y = 2

Y = +1

Y = +1

on moving down the group in the alkali metals, the size of the atom increases and the effect of the nuclear charge gets decreased. Due to this factors, the electron of potassium which is located outer gets lost easily as compared to Na. therefore, potassium reacts higher than Na.

NaOH and water are formed as a result of hydrolysis of Sodium peroxide when it is dissolved in water.

Na₂O_2(s) + 2H₂O_(l) → 2NaOH_(aq) + H₂O_2(aq)

Sodium peroxide is formed when sodium reacts with oxygen while heating it in presence of air. The reaction proceeds as shown below:

2Na_(s) + O_2(s) → Na₂O_2(s)

The nitrates are made by dissolution of the carbonates in dilute nitric acid. Magnesium nitrate crystallises with six molecules of water, whereas barium nitrate crystallises as the anhydrous salt. This again shows a decreasing tendency to form hydrates with increasing size and decreasing hydration enthalpy. All of them decompose on heating to give the oxide like lithium nitrate.

On exposure to atmosphere, it absorbs moisture and carbon dioxide to form Calcium hydroxide and Calcium carbonate. 

CaO +CO₂ ---> CaCO₃ 

CaO + H₂O ----> Ca(OH)₂ 

Note; The addition of limited amount of water breaks the lump of lime. This process is called slaking of lime

The sulphates of the alkaline earth metals are all white solids and stable to heat. BeSO₄, and MgSO₄ are readily soluble in water; the solubility decreases from CaSO₄ to BaSO₄. The greater hydration enthalpies of Be²⁺ and Mg²⁺ ions overcome the lattice enthalpy factor and therefore their sulphates are soluble in water.

Radium salts are used in radiotherapy, for example, in the treatment of cancer.

The oxides and hydroxides of both Be and Al are amphoteric and dissolve in sodium hydroxide as well as in hydrochloric acid. 

 BeO + 2HCl → BeCl₂ + H₂O 

BeO + 2NaOH → Na₂BeO₂ + H₂O 

Al₂O₃ + 6HCl → 2AlCl₃ + H₂O

Calcium, strontium and barium impart characteristic brick red, crimson and apple green colours respectively to the flame. In flame the electrons are excited to higher energy levels and when they drop back to the ground state, energy is emitted in the form of visible light.

Cement is an important building material. It was first introduced in England in 1824 by Joseph Asphdin. It is also called Portland cement because it resembles with the natural limestone quarried in the Isle of Portland, England. Cement is a product obtained by combining a material rich in lime, CaO with other material such as clay which contains silica, SiO₂ along with the oxides of aluminium, iron and magnesium. The average composition of Portland cement is : CaO, 50- 60%; SiO₂, 20-25%; Al₂O₃, 5-10%; MgO, 2- 3%; Fe₂O₃, 1-2% and SO₃, 1-2%. For a good quality cement, the ratio of silica (SiO₂) to alumina (Al₂O₃) should be between 2.5 and 4 and the ratio of lime (CaO) to the total of the oxides of silicon (SiO₂) aluminium (Al₂O₃) and iron (Fe₂O₃) should be as close as possible to 2. The raw materials for the manufacture of cement are limestone and clay. When clay and lime are strongly heated together they fuse and react to form ‘cement clinker’. This clinker is mixed with 2-3% by weight of gypsum (CaSO₄·2H₂O) to form cement. Thus important ingredients present in Portland cement are dicalcium silicate (Ca₂SiO₄) 26%, tricalcium silicate (Ca₃SiO₅) 51% and tricalcium aluminate (Ca₃Al₂O₆) 11%

 Nacl, CaCO₃ and NH₃ 

The properties of berrylium the first member of the alkaline earth metal, differ from the rest of the member. Its is mainly because of 

• Its small size and high polarizing power. 

• Relatively high electro negativity and ionization energy as compared to other members. 

• Absence of vacant d – orbitals in its valence shell.

The ionic radius of Be²⁺ is estimated to be 31 pm; the charge/radius ratio is nearly the same as that of the Al³⁺ ion. Hence beryllium resembles aluminium in some ways. Some of the similarities are: 

(i) Like aluminium, beryllium is not readily attacked by acids because of the presence of an oxide film on the surface of the metal. 

(ii) Beryllium hydroxide dissolves in excess of alkali to give a beryllate ion, [Be(OH)⁴] ^2– just as aluminium hydroxide gives aluminate ion, [Al(OH)⁴] ^– . 

(iii) The chlorides of both beryllium and aluminium have Cl^– bridged chloride structure in vapour phase. Both the chlorides are soluble in organic solvents and are strong Lewis acids. They are used as Friedel Craft catalysts. 

(iv) Beryllium and aluminium ions have strong tendency to form complexes, BeF₄ ^2–, AlF6 ^3– . 

Beryllium, the first member of the Group 2 metals, shows anomalous behaviour as compared to magnesium and rest of the members 

i) Beryllium has exceptionally small atomic and ionic sizes and thus does not compare well with other members of the group. Because of high ionisation enthalpy and small size it forms compounds which are largely covalent and get easily hydrolysed. 

ii) Beryllium does not exhibit coordination number more than four as in its valence shell there are only four orbitals. The remaining members of the group can have a coordination number of six by making use of d-orbitals. 

iii) The oxide and hydroxide of beryllium, unlike the hydroxides of oother elements in the group, are amphoteric in nature. 

Beryllium and magnesium are chemically inert to oxygen and water because of the formation of an oxide film on their surface. However, powdered beryllium burns brilliantly on ignition in air to give BeO and Be₃N₂. 

Magnesium is more electropositive and burns with dazzling brilliance in air to give MgO and Mg₃N₂. Calcium, strontium and barium are readily attacked by air to form the oxide and nitride. They also react with water with increasing vigour even in cold to form hydroxides.

The electrons in beryllium and magnesium are too strongly bound to get excited by flame. Hence, these elements do not impart any colour to the flame.

Alkali metals have low ionization enththalpies. Their valence electrons get excited by absorbing energy from the flame. When these electrons return to the ground state, the energy is emitted In the form of light. 

(a) If both assertion and reason are true and reason is the true explanation of the assertion.

A close similarity is observed in certain cases between the first element of a group with the second element of the following group. This is referred to as the diagonal relationship and is observed in the following pairs..Li & Mg 

Be & Al

 i) It is used in the preparation of mortar, a building material. 

(ii) It is used in white wash due to its disinfectant nature. 

(iii) It is used in glass making, in tanning industry, for the preparation of bleaching powder and for purification of sugar.

d) Slaked lime + sand + H₂O

(i) Sodium carbonate :for softening of hard water ,laboratory reagent. 

(ii) Sodium hydroxide: in the manufacture of soap, in the purification of bauxite. 

(iii) Sodium hydrogen carbonate: as a mild antiseptic, as an antacid.

Carbides of both the metal reacts with water liberating methane gas. 

Be₂C + 4H₂O → 2Be (OH)₂ + CH₄ 

AI₄C₃ + 12H₂O → 4Al (OH)₃ + 3CH₄

(i) sodium metal:Sodium chloride can be converted into sodium by Downs process. It can be achieved by electrolysis of fused CaCl₂ (60 %) and NaCl (40%) at 1123 K in a special apparatus (Downs cell).

A graphite block is the anode while steel is made the cathode. Metallic Ca and Na are formed at the cathode. Molten Na is supported by dipping in kerosene.

Nacl →Electrolysis Na⁺ + Cl^–

(Molten) At Cathode: 

Na⁺ +e^– → Na At Anode: 

Cl^– - e^– → Cl

(ii)Sodium Hydroxide: By electrolyzing a solution of sodium chloride, we can get Sodium hydroxide. This process is commonly known as Castner- Kellner process. The process is carried out using a mercury cathode and a carbon anode. Sodium metal, deposited at cathode forms an Amalgam by combining with Mercury.

Cathode: Na⁺ +e^– →Hg Na-Amalgam 

Anode; 2 Cl^– → Cl₂ + 2e^– 

Cl + Cl → Cl₂

(iii) Sodium peroxide: After Na metal is gotten from Downs process, it is heated on Aluminium trays in presence of air(without CO₂) to form Sodium peroxide.

2Na + O_2(air) → Na₂O₂

(iv) Sodium carbonate: Sodium hydrogen carbonate is obtained as a precipitate by reacting sodium chloride with ammonium hydrogen carbonate. The resultant crystals can be heated to obtain Sodium Carbonate.

2NH₂ + H₂O → (NH₄)₂CO₃

(NH₄)₂CO₃ + H₂O + CO₂ → 2NH₄HCO₃

2NH₄HCO₃ + NaCl → NH₄Cl + NaHCO₃

The resultant crystals can be heated to obtain Sodium Carbonate.

2NaHCO₃ → Na₂CO₃+ CO₂ + H₂O

Beryllium chloride reacts vigorously and exothermically with water with the evolution of acidic, steamy hydrogen chloride gas. This is typical of covalent chlorides. In the first instance, it reacts to give hydrated beryllium ions, [Be (H₂O)₄]²⁺, and chloride ions. But the hydrated beryllium ions (called tetraaquaberyllium ions) are quite strongly acidic. The small beryllium ion at the centre attracts the electrons in the bonds towards itself, and that makes the hydrogen atoms in the water even more positive than they usually are. If the solution is hot and concentrated (as it is likely to be if water is added to solid beryllium chloride - a very exothermic reaction), chloride ions can remove one or more of these hydrogen ions to produce hydrogen chloride gas.