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Answer is : (b) It affects photosynthetic tissue of the infected plant

Tobacco Mosaic Virus (TMV) affects photosynthetic tissue of the infected plant. Other statements can be corrected as TMV affects all dicotyledonous plants, of which most important are tobacco and tomato. But it does not affect any monocotyledonous plant. TMV is a ssRNA virus, it infects a wide range of plants, especially tobacco and other members of the family Solanaceae. TMV does not infect gymnosperms.

Answer is : (c) Waste products diffuse out of placenta into maternal blood

Placenta allows the foetus to transfer waste products to the mother’s blood. Other statements can be corrected as Placenta gives protection against most bacteria and does not allow infections to enter the foetus.

Placenta allows gaseous exchange via the mother’s blood supply, i.e. it allows diffusion of O₂ and CO₂. Placenta produces hormones like human Chorionic Gonadotropin (hCG), progesterone, oestrogen and human Placental Lactogen (hPL).

Answer is : (a) (i) < (iii) < (iv) < (ii)

pH stands for potenz (power) of hydrogen. The pH values for acidic solution ranges from 0 to 7, for pure water its value is 7 and for basic solution, it ranges from 7-14.

As HCl is a strong acid, the pH value will be least. On the other hand, KOH is a strong base, its pH value will be maximum, tomato juice contains citric acid which is a weak acid, so its pH value will be more than HCl, but will be less than H₂O and KOH.

Thus, the correct order of pH values will be

(i) < (iii) < (iv) < (ii)

Correct option: (A) (i) < (iii) < (iv) < (ii)

Correct option is (c) maximum principal quantum number of any element of the period

Since, each period starts with the filling of electrons in a new principal quantum number, therefore the period number in the long form of the periodic table refers to the maximum principal quantum number of any element in the period. Thus, period number = maximum n of any element. (where, n = principal quantum number)

Answer is : (a) Cu

The metals that are present below hydrogen in reactivity series will not produce hydrogen gas in reaction with hydrochloric acid. Among the given metals, Cu is present below H in reactivity series, i.e. it is less reactive than H, will not produce H₂ gas in reaction with HCl acid.

Correct option (C)   A₀/10

Explanation:

M_H2SO4 = 0.5

V_H2SO4 =  0.2

n_H2SO4  =  0.1

no of mole of ‘S’ atom = 0.1

∴  no of ‘s’ atom = 0.1 A₀

=  A₀/10 

Correct option  (B) exactly three of the four shapes 

Explanation:

We can cover the plane using squares definitely using equilateral triangle, we can also cover the plane. Also regular hexagon is made of equilateral triangles. But pentagon cannot cover the plane because of its shape. 

Answer is : (b) storing and secreting bile

The gall bladder is involved in storing and secreting bile. The gall bladder is a pear-shaped, hollow structure located under the liver and on the right side of the abdomen. Its primary function is to store and concentrate bile, a yellow brown digestive enzyme produced by the liver.

Correct option  (B) antigen A and B on RBCs, but neither anti-A nor anti-B antibodies in plasma 

Explanation:

Correct option  (B) Oxidative phosphorylation

Explanation:

The process of electron from glucose to molecular oxygen in bacteria and mitochondrion is occur by electron transport system which leads to oxidative phosphorylation. 

Answer is : (d) Vitamin-K

Vitamin-K is a cofactor for the enzyme responsible for chemical reactions that maintains blood clotting factors : prothrombin; factor VII, IX, X; and proteins. Thus vitamin-K plays a key role in helping the blood clot thereby preventing excessive bleeding.

Correct option  (C) Annelida

Explanation:

Metameric segmentation is present in

(1)  Annelida 

(2)  Arthropoda

(3)  Chordata  

Correct option is (c) anthocyanins

Anthocyanins are water soluble vacuolar pigments that may appear red, purple or blue depending on pH . It is impermeable to cell membranes of plants and can leak out only when membrane is damaged or dead.

Answer is : (d) the brightness of the image reduces

When a lens is cut into half or its half part is blackened, image is formed at same place but its intensity is reduced.

Correct option  (B) DNA with 30% cytosine

Explanation:

Melting temperature of DNA ∝ GC content 

Answer is : (c) The centromeres separate at the onset of anaphase

In anaphase, sister chromatids separate from centromeres so, number of chromosome becomes double. Other statements about mitosis can be corrected as Mitosis is a single nuclear division that results in two nuclei.

Synapsis takes place during prophase-I of meiosis not during mitosis. Non-sister chromatids recombine during prophase-I of meiosis. During mitosis, each sister chromatid separates and moves to opposite pole of the cell at anaphase.

Answer is : (d) 49

Total number of students = 50

Average marks of student = 47.5

∴Total marks of students

= 50x 47.5 = 2375

Now, the student get integer marks

Hence, the maximum number of students we will divide total mark by 48.

∴ 2375/48 = 49

Correct option  (C) Arrhenius frequency factor

Explanation:

K = Ae^–Ea/RT 

T →∞  k = A

Correct option  (B) Cr > Pb > Cu > Ag

Explanation :

SRP ↓ Reducing power↑

Correct option  (D)

Explanation:

Oxyhaemoglobin dissociation curve is sigmoid shaped.

Correct option  (A) Animals are distributed throughout the curve with the smaller animals towards the left and progressively bigger animals towards the right.

Explanation:

The metabolic theory of Ecology (MTE) is an extension of Kleiber's law and states that the metabolic rate of organism is the fundamental biological rate that governs most observed patterns in ecology

Correct option  (A) P-ii, Q-i, R-iv, S-v

Explanation:

Phenylketonuria is due to non-conversion of phenylalanine into tyrosine. Albinism is non-synthesis of melanin pigment. Homocystinuria is associated with methionine metabolism. Argininemia is associated with urea synthesis. 

Correct option is (a) phosphatidylcholine

Phosphatidylcholine is a class of phospholipids that are a major component of biological membranes (i.e. nerve cell membrane). It functions in the production of brain chemical called acetylcholine used for nerve impulse transmission at the synapse.

Answer is : (b) ii → i → iii

The plants in the order (fastest to slowest) in which they will dry up is ii → i → iii.

Relative humidity is the amount of water vapour present in air expressed as a percentage of the amount needed for saturation at the same temperature. As plants transpire, the humidity around saturates leaves with water vapour. When relative humidity levels are too high or there is a lack of air circulation, a plant cannot make water evaporate by transpiration or draw nutrients from the soil. Therefore 95% relative humidity will dry up the slowest, and the 45% relative humidity with blowing wind will dry up the fastest.

Correct option(B) ii, i, iii

Correct option:(C) same alleles of the same gene at the same locus

Explanation:

Sister chromatids are identical DNA molecules (In somatic cells)

Correct option(C) Slower heart rate

Explanation:

Infants have higher heart rate

Correct option(A) Provide him sugar

Explanation:

Insulin lowers blood sugar level and in this case brain is getting inadequate sugar/ glucose

Correct option is (c) t₂ > t₁ 

Time for downward journey is higher as ball can be thrown with any velocity but its downward velocity is always less than or equal to terminal velocity.

Answer is : (a) 1

The given value of n = 3 suggests that the shell is 3. For n = 1, l has 3 values, i.e. +1, 0 and −1 hence there occur 3 orbitals in p-subshell namely p_x, p_y and p_z. Thus, the given values for n = 3, l = 1 and m_l = 0 suggests that the orbital is 3p_y. Hence, the maximum number of orbitals that can be identified with given quantum number is only 1.

Correct option is (a) x = 0.4 Å

Force is zero when potential energy is minimum.

Correct option is (d) highest occupied energy level at absolute zero kelvin upto which every possible energy levels are filled

Fermi energy level is last filled energy level at zero kelvin.

Correct option is (d) sun changes its position rapidly

As sun changes its position rapidly, so reflector of solar cooker is to be adjusted nearly in every 1/2 hour duration.

Answer is : (d) Tropical evergreen forests

Diversity of species is highest in the tropical evergreen forests primarily because there are fewer ecological obstacles for biodiversity. Like the climate is wet and warm, plants and animals have the greatest access to consistent energy, water and carbon, etc. This reduces the selection for traits that emphasise the ability to withstand environmental stresses such as cold and drought, etc., and promotes higher rates of speciation.

Correct option  (B) Tropical rain forest

Explanation:

Tropical rain forest shows vertical zonation i.e. stratification.

Correct option  (D) Diencephalon 

Explanation:

Cavity of Diancephelon is called as diocoel or third ventricle.

Answer is : (d) Glucose to CO₂ and H₂O

Conversion of glucose to CO₂ and H₂O requires oxygen. In aerobic respiration glucose reacts with oxygen forming ATP, carbon dioxide and water are released as byproducts.

C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + ATP

Correct option is (d) Lipids

Among the given options, except lipids all are polymers. These are formed by the polymerisation of monomers. The basic unit of lipid are fatty acids and glycerol molecules that do not form repetitive chains. Instead they form triglycerides from 3 fatty acids and one glycerol molecules. Protein monomers are amino acids and they bond together in repetitive chains just as carbohydrate monomers are monosaccharides.

Correct option is (c) haplodiplontic, diplontic

Ectocarpus and Fucus respectively show haplodiplontic and diplontic life cycle. In Ectocarpus, sporic meiosis occurs and haploid biflagellate meiozoospores are formed. They germinate to produce gametophytic thalli. The gametophytes liberate gametes which fuse to form diploid zygote which gives rise to a diploid plant. In Fucus, there is a single somatic phase. It is diploid and produces haploid gametes. They fuse during fertilisation to give rise to diploid individual.

Correct option is (d) Chlamydomonas 

Zygotic meiosis is represented in the haplontic life cycle of many algae including Chlamydomonas. In such a life cycle, all cells are haploid except zygote. This is because meiosis occurs in the zygote itself resulting into four haploid cells that give rise to haploid plants.

Correct option is (b) ammonia and urea

Ornithine cycle removes both ammonia and urea from the blood. It converts ammonia into urea (in liver) and transports it to kidneys by the blood. Hence, it plays a key role in detoxification of our blood. This cycle occurs in the liver.

Answer is : (d) no water coming out

When box with hole is in free fall, both water and box cover equal distance downwards in equal time.

Hence, no water comes out of hole in free fall of box.

Correct option  (B) heat killed S-strain combined with R-strain 

Explanation:

In Griffith experiment, mice died when injected with combination heat killed s-strain + Live R strain which resulted in the transformation of R II into S III form.

Correct option (C) T(L) and M(L) will fall, T(M) will remain same and M(M) will increase 

Explanation:

Desert lizard is an ectotherm (poikilotherm) whose body temperature varies according to environmental temperature.

So at 15ºC T(L) will fall due to fall in T(M)

While mouse is an endotherm (Homeotherm) whose body temperature remains constant always due to variation is metabolic rate

In homeotherms metabolic rate is inversely proportional to environmental temperature. So at 15ºC T(M) remain same and M((M) will increased.  

Answer is : (b) 5 ml

Put x time of water of 110 ml to container and take y time of water of 25 ml from container.

Then, container contains 110x - 25y

= 5(22x - 5y)

∴ Container contains multiple of 5.

∴ Smallest amount of water be measure accurately 5 ml.

Answer is : (b) 7 times

Time taken by Ajay and Vijay to meet first time anywhere on the path

= Distance/Relative speed = 1.2/8.6 = 0.6 h

Time taken by Ajay and Sanjay to meet anywhere

= Distance/Relative speed \(=\frac{1.2}{9+6}\) = 0.8 h

The number of times Ajay and Sanjay meets anywhere on the path by the time Ajay and Vijay meets each other for the first time = 36/4.8 = 7 1/2, i.e. 7 times.

Answer is : (c) Trypsin

In duodenum, trypsin enzyme catalyses the hydrolysis of peptide bonds, breaking down proteins into smaller peptides. Amylase hydrolyses starch into maltose inside the mouth. Lipase breaks down dietary fats into fatty acids and glycerol. Maltase hydrolyses maltose into simple sugar glucose.

Correct option is (d) None of these

Nuclear density is a constant (ρ = 2.38 × 10¹⁷ kg m⁻³). It is independent of nuclear size and number of nucleons. So, ratio is 1:1.