Trending ▼   ResFinder  

CBSE Class 12 Board Exam 2020 : Biology (Series 2)

19 pages, 140 questions, 0 questions with responses, 0 total responses,    0    0
cbse12
   		+Fave Message
ProfileTimelineUploadsQ & A
 Home > cbse12 >

Instantly get Model Answers to questions on this ResPaper. Try now!
NEW ResPaper Exclusive!

Formatting page ...

H$moS> Z . Code No. amob Z . 57/2/1 narjmWu H$moS >H$mo C ma-nwp VH$m Ho$ _wI-n >na Ad ` {bIo & Roll No. Candidates must write the Code on the title page of the answer-book. (I) ZmoQ> H $n`m Om M H$a b| {H$ Bg Z-n _o _w{ V n > 19 h & (II) Z-n _| Xm{hZo hmW H$s Amoa {XE JE H$moS >Z ~a H$mo N>m C ma-nwp VH$m Ho$ _wI-n > na {bI| & (III) H $n`m Om M H$a b| {H$ Bg Z-n _| >27 Z h & H $n`m Z H$m C ma {bIZm ew $ H$aZo go nhbo, C ma-nwp VH$m _| Z H$m H $_m H$ Ad ` {bI| & Bg Z-n H$mo n T>Zo Ho$ {bE 15 {_ZQ >H$m g_` {X`m J`m h & Z-n H$m {dVaU nydm _| 10.15 ~Oo {H$`m OmEJm & 10.15 ~Oo go 10.30 ~Oo VH$ N>m Ho$db Z-n H$mo n T>|Jo Am a Bg Ad{Y Ho$ Xm amZ do C ma-nwp VH$m na H$moB C ma Zht {bI|Jo & (IV) (V) NOTE (I) Please check that this question paper contains 19 printed pages. (II) Code number given on the right hand side of the question paper should be written on the title page of the answer-book by the candidate. (III) Please check that this question paper contains 27 questions. (IV) Please write down the Serial Number of the question in the answer-book before attempting it. (V) 15 minute time has been allotted to read this question paper. The question paper will be distributed at 10.15 a.m. From 10.15 a.m. to 10.30 a.m., the students will read the question paper only and will not write any answer on the answer-book during this period. Ord {dkmZ (g mp VH$) BIOLOGY (Theory) {ZYm [aV g_` : 3 K Q>o A{YH$V_ A H$ : 70 Time allowed : 3 hours .57/2/1 Maximum Marks : 70 1 P.T.O. gm_m ` {ZX}e : {Z Z{b{IV {ZX}em| H$mo ~h V gmdYmZr go n{ T>E Am a CZH$m g Vr go nmbZ H$s{OE : (i) Z-n nm M I S>m| _ | {d^m{OV {H$`m J`m h H$, I, J, K Am a L> & (ii) Bg Z-n _| 27 Z h & g^r Z A{Zdm` h & (iii) I S> H$ _| Z g `m 1 go 5 VH$ ~h {dH$ nr` Z h , `oH$ Z 1 A H$ H$m h & (iv) I S> I _| Z g `m 6 go 12 VH$ bKw-C mar` H$ma-I Ho$ Z h , `oH$ Z 2 A H$m| H$m h & (v) I S> J _| Z g `m 13 go 21 VH$ bKw-C mar` H$ma-II Ho$ Z h , `oH$ Z 3 A H$m| H$m h & (vi) I S> K _| Z g `m 22 go 24 VH$ bKw-C mar` H$ma-III Ho$ Z h , `oH$ Z 3 A H$m| H$m h & (vii) I S> L> _| Z g `m 25 go 27 VH$ XrK -C mar` Z h , `oH$ Z 5 A H$m| H$m h & (viii) C ma g {j VWm q~X dma hmoZo Mm{hE & (ix) Bg Z-n _| g_J na H$moB {dH$ n Zht h & VWm{n EH$-EH$ A H$ dmbo Xmo Zm| _|, Xmo-Xmo A H$m| dmbo EH$ Z _ o, VrZ-VrZ A H$m| dmbo Xmo Zm| _ o Am a nm M-nm M A H$m| dmbo VrZm| Zm| _ o Am V[aH$ {dH$ n {XE JE h & Eogo Zm| _| Ho$db EH$ hr {dH$ n H$m C ma Xr{OE & (x) Ohm Amd `H$ hmo, dhm gm \$-gwWam, AmZwnm{VH$ VWm g_w{MV Zm_m {H$V {M ~ZmBE & (xi) BgHo$ A{V[a $, Amd `H$VmZwgma, `oH$ I S> Am a Z Ho$ gmW `Wmo{MV {ZX}e {XE JE h & I S> H$ ZmoQ> : {Z Z{b{IV Zm| _| `oH$ Z _| {XE JE {dH$ nm| go ghr {dH$ n MwZH$a {b{IE & 1. AZw _r ` namJUr nw n dnamJUr hmoVo h `m|{H$ (A) do C^`qbJr ({ qbJr) nw n hmoVo h Omo H$^r ^r AZmd V Zht hmoVo & (B) do C^`qbJr ({ qbJr) VWm AZmd V nw n hmoVo h & (C) do EH$qbJr hmoVo h & (D) namJH$moe Ho$ \w$Q>Z go nhbo hr d{V H$mJ n[an d hmo OmVm h & AWdm Bg_| Mb ~rOmUwAm| mam Ab {JH$ OZZ hmoVm h (A) no{Zgr{b`_ (B) hmBS >m (C) n O (D) b {_S>mo_moZmg .57/2/1 2 1 1 General Instructions : Read the following instructions very carefully and strictly follow them : (i) Question paper comprises five sections A, B, C, D and E. (ii) There are 27 questions in the question paper. All questions are compulsory. (iii) Section A Questions no. 1 to 5 are multiple choice questions, carrying 1 mark each. (iv) Section B Questions no. 6 to 12 are short-answer questions type-I, carrying 2 marks each. (v) Section C Questions no. 13 to 21 are short-answer questions type-II, carrying 3 marks each. (vi) Section D Questions no. 22 to 24 are short-answer questions type-III, carrying 3 marks each. (vii) Section E Questions no. 25 to 27 are long-answer questions, carrying 5 marks each. (viii) Answers should be brief and to the point. (ix) There is no overall choice in the question paper. However, an internal choice has been provided in two questions of 1 mark, one question of 2 marks, two questions of 3 marks and three questions of 5 marks. Only one of the choices in such questions have to be attempted. (x) The diagrams drawn should be neat, proportionate and properly labelled, wherever necessary. (xi) In addition to this, separate instructions are given with each section and question, wherever necessary. SECTION A Note : Choose the correct option from the choices given in each of the following questions. 1. Cleistogamous flowers are self-pollinated because (A) they are bisexual flowers which do not open at all. (B) they are bisexual and open flowers. (C) they are unisexual. (D) their stigma matures before the anthers dehisce. OR 1 Asexual reproduction by zoospores is observed in 1 (A) Penicillium (B) Hydra (C) Sponge (D) Chlamydomonas .57/2/1 3 P.T.O. 2. bwB nm Ma mam {H$`m J`m `moJ O d {dH$mg Ho$ Bg {g m V H$m g_W Z H$aVm h 1 (A) 3. dV: OZZ {g m V (B) OrdZ nhbo go {d _mZ OrdZ go hr C n hmoVm h (C) AOrdm OZZ (D) {~J ~ J {g m V _mZdm| _| Q>mB\$m BS> H$s nw{ > hoVw {ZXmZm _H$ narjU h 1 (A) 4. E{bgm (B) {dS>mb (C) E_.Ama.AmB . (D) C ~doYZ O d-g{H $` AUw {OgH$m Cn`moJ A J {VamonU Ho$ Xm amZ {Vajm -{ZamoYH$ (B `yZmog og|Q> ) Ho$ $n _| {H$`m OmVm h (A) (B) (C) (D) 1 Q>oQ >mgmB brZ gmB bmo nmo[aZ-E Q> {Q>Z Q > Q>mo_mBgrZ AWdm Zrbr H $m {V H$m Cn`moJ Bg g X^ _| {H$`m OmVm h 1 (A) 5. Ob g ajU hoVw ~m Y ~ZmZm (B) ~ S>r _m m _| _ ` C nmXZ (C) dm{hV _b H$m CnMma (D) e dmb \w$Q>Z (A Jb by_) H$m {Z` U {Z Z{b{IV _| go H$m Z-gm nmaOrdr `moJm| H$m C nmX Zht h (A) (B) (C) (D) .57/2/1 nr S>H$-n {VamoYr \$gb H$s {H$ _ Im mZm| _| C nm f{UH$ _mZ Ama.-S>r.EZ.E. VH$ZrH$ mam B gwbrZ H$m C nmXZ Obm^md- {VamoYr \$gb| 4 ? 1 2. 3. 4. The theory of evolution supported by the experiment conducted by Louis Pasteur is (A) Spontaneous generation theory (B) Life comes only from pre-existing life (C) Abiogenesis of life (D) Big bang theory The diagnostic test that confirms typhoid in humans is (A) ELISA (B) Widal (C) MRI (D) Amniocentesis 1 The bioactive molecule used as an immunosuppressive agent during organ transplant is (A) Tetracyclin (B) Cyclosporin-A (C) Statin (D) Streptomycin 1 1 OR Blue revolution refers to 5. 1 (A) construction of water dams for conservation of water (B) production of fish in large quantities (C) sewage treatment (D) controlling algal bloom Which one of the following is not the product of transgenic experiments ? (A) Pest-resistant crop variety (B) High nutritional value in grains (C) Production of insulin by rDNA technique (D) Drought-resistant crops .57/2/1 5 1 P.T.O. I S> I 6. 7. 8. _mZd _| (a) AY gy mUw (AY gy r H$mo{eH$m), VWm g `m {b{IE & _| gy JwUVm VWm JwUgy m| H$s 2 AgwJw{UVm (Eo `y bmoBS>r) `m h ? _mZd _| (a) EH$ A{b Jgy H$s A{YH$Vm, VWm (b) _mXmAm| ({ `m|) _| EH$ qbJ JwUgy H$s hm{Z Ho$ H$maU JwUgy r` (H $mo_mogmo_r`) {dH$ma H$m Zm_ {b{IE & {Z Z{b{IV Hy$Q>m| (H$moS>m Zm|) _| EH$ H$m`m _H$ A Va {b{IE (a) 9. (b) `w _H$m| : (b) VWm UAA {d{e > VWm An m{gV (a) ZrMo Xr JB gyMr _| go {H$ ht Xmo {eewYmZr m{U`m| H$mo nhMmZ H$a {b{IE 2 2 AUG (i) (ii) (iii) (iv) (v) (vi) : bo_a Y ~oXma H$ H$g C S>Z-\ $bo Oa ~m ~H $Q> V _m{Z`mB ^o{ S>`m >N>Ny> Xa Am Q >o{b`m Ho$ {eewYmZr m{U AZwHy$br {d{H$aU X{e V H$aVo h & H$WZ H$s `m`g JVVm {g H$s{OE & 2 ZdOmV {eew H$mo _m mam XmZ H$s OmZo dmbr {Vajm Ho$ H$ma H$m Zm_ {b{IE & `h H $go hmoVr h ? 2 11. Xmo mW{_H$ bgrH$m^ A Jm| Ho$ Zm_ {b{IE & Q>r-bgrH$mUwAm| H$m _h d {b{IE & 2 12. X X _ A~w X gwX_ A~w X go {H$g H$ma {^ h ? Hw$N> amo{J`m| H$m CnMma -B Q>a\o$am Zm| go `m| {H$`m OmVm h ? AWdm Cg hm _m}Z H$m Zm_ {b{IE Omo _ Q>rnb Am `yboeZ E p ~ `mo Q >m g \$a (MOET) VH$ZrH$ mam Jm` H$mo {X`m OmVm h & Bg hm _m}Z H$m H$m` {b{IE & (b) 10. .57/2/1 6 2 2 SECTION B 6. 7. 8. 9. Write the ploidy and number of chromosomes in human (a) meiocytes, and (b) gametes. 2 What is aneuploidy ? Name a chromosomal disorder in humans caused due to (a) gain of an autosome, and (b) loss of a sex chromosome in females. 2 State a functional difference between the following codons : 2 (b) AUG and UAA (b) Specific and Degenerate (a) Identify any two marsupials from the list given below : (b) 10. 11. 12. (i) Lemur (ii) Spotted cuscus (iii) Flying phalanger (iv) Bobcat (v) Tasmanian wolf (vi) Mole Australian marsupials exhibit adaptive radiation. Justify the statement. 2 Name the type of immunity the mother provides the newborn baby. How does it happen ? 2 Name the two primary lymphoid organs. State the importance of T-lymphocytes. 2 How are malignant tumours different from benign tumours ? Why are some patients treated with -interferons ? 2 OR Name the hormone with which a cow is administered using MOET technology. State the function of this hormone. .57/2/1 7 2 P.T.O. I S> J 13. 14. EH$ nw nr nmXn Ho$ rHo$ga H$m namJU hmoZo Ho$ n MmV H$s Ad Wm H$s AZw W-H$mQ> H$m AmaoI ~ZmBE & {Z Z{b{IV H$mo Zm_m {H$V H$s{OE : (a) namJ H$Um| H$m A Hw$aU Xem Vo h E d{V H$mJ (b) d{V H$m (c) ~rOm S> ma VH$ nh MVr h B namJ Z{bH$m (d) ^ yU H$mof (e) A S> CnH$aU Ho$ KQ>H$ 3 {XE JE {M H$m A ``Z H$s{OE : A EH$ ^ yUmd Wm h Omo B _| $nm V[aV hmo OmVm h VWm _mZd { `m| Ho$ J^m e` A V: Va _| A Vam}{nV hmo OmVm h & (a) A, B VWm (b) _mZdm| _| ^ yUr` n[adY Z Ho$ Xm amZ H$mbm Va _| BgHo$ C Ed D ^mJm| H$mo nhMmZ H$a {b{IE & AWdm .57/2/1 8 C VWm D H$m `m hmoVm h ? 3 SECTION C 13. Draw a longitudinal section of the pistil from a flowering plant, where pollination has occurred. Label the following : 14. (a) Stigma showing germinating pollen grains (b) Style (c) Pollen tube reaching the micropyle of the ovule (d) Embryo sac (e) Components of the egg apparatus 3 Study the given diagram : A is an embryonic stage that gets transformed into B, which in turn gets implanted in the endometrium in human females. (a) Identify A, B and its parts C and D. (b) State the fate of C and D in the course of embryonic development in humans. 3 OR .57/2/1 9 P.T.O. 15. 16. 17. 18. (a) ZrMo {XE JE {M H$mo nhMm{ZE VWm BgHo$ H$a {b{IE & (b) E H$m B, C, D Ed E Ho$ ^mJm| H$mo ^r nhMmZ 3 H$m` ^r {b{IE & EH$ gm_m ` X n{V H$mo nhbr g VmZ C n hmoVr h , Omo hr_mo\$s{b`m go J V h & BgH$s g ^m `Vm H$mo Xem Zo Ho$ {bE EH$ H $m g ~ZmBE & Bg X n{V go n Xm hmoZo dmbr gm_m ` VWm hr_mo\$s{b`mJ V g V{V H$s qbJmZwgma g ^m `Vm H$m C boI H$s{OE & 3 {H$gr nm[aV _| _yb A dofH$ Om{V Ho$ EH$ Z Z M >mZ na AmH $_U go ma ^ H$a Ma_md Wm g_wXm` VH$ Ho$ AZwH $_U Ho$ {d{^ MaUm| H$m dU Z H$s{OE & Bg H$ma Ho$ AZwH $_U H$m Zm_ {b{IE & 3 ZJam| Ho$ An{e > Ob Ed Am mo{JH$ ~{h: md H$mo mH ${VH$ Ob moVm| _ o {Z_w $ H$aZo go Obr` OrdZ na {dZmeH$mar (KmVH$) ^md n S> ahm h & Bg ~{h: md H$mo mH ${VH$ Ob moVm| _| {dg{O V H$aZo go nhbo BgHo$ dm {N>V O {dH$ CnMma H$s `m `m H$s{OE & 3 gy _- dY Z VH$ZrH$ Ho$ H$moB Xmo bm^m| H$m C oI H$s{OE & `moJembm _| Bg {H $`m H$mo {H$g H$ma {H$`m OmVm h ? Bg VH$ZrH$ mam `mdgm{`H$ Va na CJmE OmZo dmbo {H$ ht Xmo _h dnyU Im -nmXnm| Ho$ Zm_ {b{IE & 3 .57/2/1 10 15. (a) Identify the figure given below and also identify the parts B, C, D and E. (b) State the function of E. 3 A normal couple has their first child, who is haemophilic. Work out a cross to show how it is possible. State the possibility of the normal and the haemophilic children, along with their sexes, that can be born to them. 16. 3 Starting from the pioneer species, trace the sequence that follows in an ecological succession on a bare rock, until climax community is reached in an ecosystem. Name this type of succession. 17. 3 The release of municipal wastewater and industrial waste into our natural water bodies is causing disastrous effect to the aquatic life. Explain the biological treatment that should be given to it before releasing into the natural water bodies. 18. 3 Mention any two advantages of micropropagation technique. Write how its process is carried out in the laboratory. Name any two important food plants grown commercially by this method. .57/2/1 11 3 P.T.O. 19. ~ grbg Wy[a {OE|{gg O~ EH$ {d{e > H$sQ> Ho$ eara _| {d > hmoVm h , Vmo dh H$sQ> _a OmVm h , na Vw `h d` A ^m{dV ahVm h & g_PmBE {H$ `h {H$g H$ma g ^d h & 20. (a) EH$ nm[aV _| naOrdm| _ o {H$g H$ma H$m AZwHy$bZ h Am {H$ dh AnZo nanmofr Ho$ gmW gh-Ap V d ~ZmE aI gH|$ & g_PmBE & (b) naOrdr {d{e > nanmofr na hr Am{lV hmoVo h VWm gh-{dH${gV hmoVo h & `{X nanmofr naOrdr Ho$ {V {VamoYr AWdm A drH$ma H$aZo H$m VarH$m {dH${gV H$aVm h , Vmo naOrdr {H$g H$ma AZw{H $`m H$aoJm ? 3 3 AWdm 21. (a) {H$gr nm[aV _| nmE OmZo dmbo AmXe {na {_S> H$m Zm_ {b{IE & BgH$mo Vrgao nmofU Va VH$ ~ZmBE VWm CZHo$ Zm_ {b{IE & (b) {H$gr nm[aV H$mo gy` go 1,000,000 J gm a D$Om m hmoVr h & H $_e: W_ Ed Vrgao nmofr Va na Cnb Y D$Om H$s _m m {b{IE & 3 d p dH$ Va na H$m~ Z H$m p WarH$aU Ord_ S>b _| H$me-g bofU Ho$ mam hmoVm h & (a) {H$ ht Eogo Xmo VarH$m| H$s `m `m H$s{OE {OZHo$ mam mH ${VH$ H $_m| mam dm`w_ S>b _| H$m~ Z H$s nwZamny{V (dmngr) hmoVr h & (b) _mZd Ho$ Eogo H$moB Xmo H$m` H$bmnm| H$s gyMr ~ZmBE {OZgo H ${V _| H$m~ Z MH $ ^m{dV hwAm hmo & .57/2/1 12 3 19. When Bacillus thuringiensis enters a certain insect s body, the insect gets killed, but itself remains unaffected. Explain how it is possible. 20. (a) 3 Write how parasites have evolved with adaptation to co-exist with their hosts in an ecosystem. (b) Parasites are host specific and tend to co-evolve. How would the parasite respond if the host evolves a certain mechanism to resist or reject the parasite ? 3 OR (a) Name an ideal pyramid existing in an ecosystem. Construct it up to its three trophic levels along with their names. (b) The sun provides 1,000,000 J of sunlight (solar energy) to an ecosystem. Write the amount of energy that is available to the first and third trophic levels, respectively. 21. 3 Global carbon is fixed in the biosphere through photosynthesis. (a) Explain any two ways by which carbon is returned to the atmosphere through natural processes. (b) List any two human activities that have influenced the carbon cycle in nature. .57/2/1 3 13 P.T.O. I S> K 22. D$na {XE JE `d WmnH$ {Z $nU H$m A ``Z H$s{OE VWm {Z Z{b{IV Zm| Ho$ C ma Xr{OE : (a) Bg_| A H$mo nhMmZ H$a {b{IE & (b) Bg_| D H$mo nhMmZ H$a {b{IE & (c) `{X {XE JE g_` t na g_{ > KZ d H$m _mZ Cn`w $ AmaoImZwgma N h , Vmo g_w{MV g Ho$Vm| H$m Cn`moJ H$aVo h E t + 1 g_` na g_{ > KZ d H$mo g_rH$aU Ho$ $n _| {b{IE & 23. (a) ZrMo Xr JB nm br_aoO m Ibm A{^{H $`m Ho$ MH $ _| MaU {b{IE & > (b) MaU .57/2/1 B _| A VWm B H$mo nhMmZ H$a Cn`moJ {H$E OmZo dmbo E OmB_ H$m {d{e > A{^bjU {b{IE & 14 3 3 SECTION D 22. Study the schematic representation given above and answer the following questions : 23. (a) Identify A in it. (b) Identify D in it. (c) When the population density at time t is N as shown above, write the population density at time t + 1 in the form of an equation using appropriate symbols. (a) Identify steps A and B in a cycle of Polymerase Chain Reaction given below. (b) State the specific characteristic feature of the enzyme in carrying step B. .57/2/1 15 3 3 P.T.O. 24. Eg.Eb. {_ba Ho$ `moJ H$m AmaoIr` {Z $nU ZrMo {X`m J`m h & BgH$m A ``Z H$s{OE VWm {Z Z{b{IV Zm| Ho$ C ma Xr{OE : Bbo Q >moS> ~ X bm H$ d `y_ n n H$mo J g| Ob ~mha g K{Z Ob A Xa Ob {~ X H$m~ {ZH$ `m {JH$m| dmbm Ob C~bVm Ob nme _| d Ob (a) Eg.Eb. {_ba Zo AnZo `moJ g `moOZ _ o CZ n[ap W{V`m| H$mo H $go C n {H$`m Omo n dr na OrdZ H$s C n{ m go nyd _m OyX Wt (b) ? CgHo$ `moJ Ho$ A V _ o ~ZZo dmbo H$m~ {ZH$ `m {JH$ H$m Zm_ {b{IE {Ogo CgZo m (EH${ V) {H$`m & (c) {dH$mg Ho$ Cg H$ma H$m Zm_mo boI H$s{OE {OgH$m g_W Z CgHo$ `moJ mam 3 h Am & .57/2/1 16 24. Study the diagrammatic representation of S.L. Miller s experiment given below and answer the questions that follow : Electrodes Closed flask To vacuum pump Gases Water out Condenser Water in Water droplets Water containing organic compounds Boiling water Liquid water in trap (a) How did S.L. Miller create the conditions which existed before the origin of any life on Earth ? (b) Name the organic compound formed and collected at the end of his experiment. (c) .57/2/1 Mention the kind of evolution his experiment supports. 17 3 P.T.O. I S> L> 25. 26. 27. (a) _mZd H$s ewH $OZH$ Z{bH$m Ho$ AmaoIr` H$mQ> H$m {M ~ZmBE & BgHo$ {H$ ht N>: ^mJm| H$mo Zm_m {H$V H$s{OE & (b) ewH $OZZ H $_ _| em{_b nr`yf J {W hm _m}Zm| Ho$ Zm_ {b{IE VWm BZHo$ H$m`m] H$m C oI H$s{OE & AWdm (a) AmB .`y.S>r. H$mo EH$ ^mdr J^ {ZamoYH$ `w{ $ H$hm OmVm h & gm_m ` $n go gdm {YH$ Cn`moJ H$s OmZo dmbr {H$ ht Xmo AmB .`y.S>r. `w{ $`m| Ho$ Zm_ {b{IE VWm CZHo$ H$m` H$aZo Ho$ VarH$m| H$mo {b{IE & (b) {H$gr {ddm{hV X n{V H$mo ~ `H$aU H$s gbmh H$~ Xr OmVr h nw f VWm r _| {H$g H$ma g n H$aVo h ? ? Bgo H $_e: EH$ b Q>mog `w $ g dY Z _m `_ _| g d{Y V B .H$mobmB _ o b H$ MmboH$ (Amonoam Z) OrZ H$s A{^ `{ $ H$s `m `m H$s{OE & AWdm H$mo{eH$mAm| Ho$ H$ma VWm H $_ H$m Zm_ {b{IE {OgHo$ mam {df_m Jr Ho$ H$s` Ama.EZ.E. (hnRNA) ~ZVm h & {H $`merb hmoZo Ho$ {bE `h {OZ H $_m| go Jw OaVm h CgH$s {H $`m{d{Y H$m dU Z H$s{OE & {d d _| ha OJh H ${V _| nm[ap W{VH$ g VwbZ ~ZmE aIZo Ho$ {bE O d{d{dYVm g ajU Ho$ {V A `{YH$ qMVm h & VrZ H$maU XoVo h E BgH$s `m `m H$s{OE & Eogo {d{^ Cnm`m| H$mo {b{IE Omo h_mao Xoe _| ~mKm| H$s g_{ > ~ T>mZo _| ghm`H$ {g h E h & AWdm EH$sH $V O d IoVr `m h ? gmoZrnV, h[a`mUm Ho$ a_oe M S>mJa Zm_H$ {H$gmZ Zo Bg VarHo$ H$m ^mdembr T> J go {H$g H$ma Cn`moJ {H$`m {H$ dh ey ` An{e > ~ YZ _| g\$b ahm ? .57/2/1 18 5 5 5 5 5 5 SECTION E 25. (a) Draw the sectional view of a seminiferous tubule of human. Label its any six parts. (b) Name the pituitary hormones involved in the process of spermatogenesis. State their functions. 5 OR 26. (a) IUDs are said to be effective contraceptives. Name any two commonly used IUDs and write the mode of their actions. (b) When is sterilisation advised to married couples ? How is it carried out in a human male and a female, respectively ? 5 Explain the expression of lac operon genes in E. coli growing in lactose containing culture medium. 5 OR 27. Name the types of cells and the process by which hnRNA is formed. Describe the processing mechanism it undergoes before it becomes functional. 5 There is a great concern all over the world to conserve biodiversity for maintaining ecological balance in nature. Explain giving three reasons. Write different ways that have helped in increasing tiger population in our country. 5 OR What is integrated organic farming ? How did Ramesh Chandra Dagar, a farmer from Sonepat, Haryana effectively use this procedure and succeed with zero waste ? .57/2/1 19 5 P.T.O.

Formatting page ...

Formatting page ...

Formatting page ...

Formatting page ...

Formatting page ...

Formatting page ...

Formatting page ...

Formatting page ...

Formatting page ...

Formatting page ...

Formatting page ...

Formatting page ...

Formatting page ...

Formatting page ...

Formatting page ...

Formatting page ...

Formatting page ...

Formatting page ...

 

  Print intermediate debugging step

Show debugging info


 


Tags : cbse, cbse papers, cbse sample papers, cbse books, portal for cbse india, cbse question bank, central board of secondary education, cbse question papers with answers, prelims preliminary exams, pre board exam papers, cbse model test papers, solved board question papers of cbse last year, previous years solved question papers, free online cbse solved question paper, cbse syllabus, india cbse board sample questions papers, last 10 years cbse papers, cbse question papers 2017, cbse guess sample questions papers, cbse important questions, specimen / mock papers 2018.  

© 2010 - 2025 ResPaper. Terms of ServiceContact Us Advertise with us

 

cbse12 chat