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CBSE Class 12 Board Exam 2019 : Biology (Series 5)

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SET-1 H$moS> Z . Series BVM/5 Code No. amob Z . 57/5/1 narjmWu H$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. H $n`m Om M H$a b| {H$ Bg Z-n _o _w{ V n > 15 h & 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| & 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$aZo go nhbo, Z H$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 & Please check that this question paper contains 15 printed pages. 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. Please check that this question paper contains 27 questions. Please write down the Serial Number of the question before attempting it. 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 57/5/1 Maximum Marks : 70 1 P.T.O. gm_m ` {ZX}e : Z-n _| Mma I S>m| _ o Hw$b 27 Z {XE JE h & g^r Z A{Zdm` h & (ii) I S> A _| Z g `m 1 go 5 A{V bKw-C mar` Z h , `oH$ Z 1 A H$ H$m h & (iii) I S> B _| Z g `m 6 go 12 bKw-C mar` Z H$ma I Ho$ h , `oH$ Z 2 A H$m| H$m h & (iv) I S> C _| Z g `m 13 go 24 bKw-C mar` Z H$ma II Ho$ h , `oH$ Z 3 A H$m| H$m h & (v) I S> D _| Z g `m 25 go 27 XrK -C mar` Z h , `oH$ Z 5 A H$m| H$m h & (vi) Z-n _| g_J na H$moB {dH$ n Zht h , {\$a ^r 1 A H$ dmbo Xmo Zm| _|, 2 A H$m| dmbo Xmo Zm| _|, 3 A H$m| dmbo Mma Zm| _| Am a 5 A H$m| dmbo g^r VrZm| Zm| _| ^rVar M`Z{dH$ n {XE JE h & `oH$ narjmWu H$mo Eogo Zm| Ho$ Xmo {dH$ nm| _ o go H$moB EH$ Z hb H$aZm h & (vii) Amd `H$VmZwgma, {M m| H$m aoIZ gm\$-gwWam Ed `Wmo{MV bo~b hmoZm Mm{hE & (i) General Instructions : (i) There are a total of 27 questions and four sections in the question paper. All questions are compulsory. (ii) Section A contains questions number 1 to 5, very short-answer type questions of 1 mark each. (iii) Section B contains questions number 6 to 12, short-answer type I questions of 2 marks each. (iv) Section C contains questions number 13 to 24, short-answer type II questions of 3 marks each. (v) Section D contains questions number 25 to 27, long-answer type questions of 5 marks each. (vi) There is no overall choice in the question paper, however, an internal choice is provided in two questions of 1 mark, two questions of 2 marks, four questions of 3 marks and all the three questions of 5 marks. In these questions, an examinee is to attempt any one of the two given alternatives. (vii) Wherever necessary, the diagram drawn should be neat and properly labelled. 57/5/1 2 I S> A SECTION A 1. {H$gr amoJr | amoJ Ho$ bjU n[ab{jV hmoZo Ho$ g go nhbo hr amoJH$maH$ amoJmUwAm| Ho$ {ZXmZ | O d- m mo{JH$-VH$ZrH$ ghm H$ hmo gH$Vr h & Bg H$ma H$s {H$ ht Xmo VH$ZrH$m| H$m gwPmd Xr{OE & AWdm ~ {gbg WwarZ{OE {gg mam {Z{ V {Zp H $ moQ>rZ Q>m p gZ {Og $n | ~ZVm h , CgH$m C oI H$s{OE & nr S>H$ Ord Ho$ eara | h {H$g H$ma g{H $ hmo OmVm h {Oggo h CgHo$ {bE mU KmVH$ ~Z OmVm h ? 1 1 Biotechnological techniques can help to diagnose the pathogen much before the symptoms of the disease appear in the patient. Suggest any two such techniques. OR Mention the form in which inactive protein toxin is produced by Bacillus thuringiensis. How does it get activated in the pest body to kill it ? 2. p dg Mr O | nmE OmZo dmbo ~ S>o-~ S>o {N> CgH$s bmj{UH$ {deofVm h & BgHo$ {bE C maXm r OrdmUw H$m Zm {b{IE & 1 Swiss cheese is characterised by the presence of large holes. Name the bacterium responsible for it. 3. ZrMo Xem E JE S>r.EZ.E. AUw H$s AZwboIZ BH$mB | h ? X Ed Y {H$gH$m {V{Z{Y d H$aVo 1 What do X and Y represent in the transcription unit of the DNA molecule shown ? 57/5/1 3 P.T.O. 4. {Z Z{b{IV H $[aAmoQ>mBn dmbo Zw Ho$ {dH$ma H$m Zm {b{IE (a) 22 Omo S>o AqbJgy H $mo mogmo + XO (b) 22 Omo S>o AqbJgy H $mo mogmo + 21dm : 1 H $mo mogmo + XY Name the disorder in humans with the following karyotype : 5. (a) 22 pairs of autosomes + XO (b) 22 pairs of autosomes + 21st chromosome + XY EH$ Amd V~rOr nm Yo | { Jw{UV H $mo mogmo H$s g m 16 h & BgHo$ ^ yUnmof VWm {V mgm V H$mo{eH$mAm| | JwUgy m| H$s g m m hmoJr ? AWdm O~ namJH$moe | Q> nrQ> Agm m T> J go H$m H$aVr h Vmo namJH$U OrdZj Vm m| Imo XoVo h ? H$maU n Q> H$s{OE & 1 1 The diploid number of chromosomes in an angiospermic plant is 16. What will be the number of chromosomes in its endosperm and antipodal cells ? OR State the reason why pollen grains lose their viability when the tapetum in the anther is malfunctioning. I S> B SECTION B 6. ewH $mUwOZZ VWm dr goMZ | {d^oX H$s{OE & 2 Differentiate between spermiogenesis and spermiation. 7. AmnH$mo Q>a H$m EH$ b ~m nm Ym XoH$a BgH$m OrZmoQ>mBn (OrZr $n) kmV H$aZo Ho$ {bE H$hm OmVm h & Amn BgH$m OrZr $n {H$g H$ma kmV H$a|Jo ? m m H$s{OE & You are given a tall pea plant and asked to find its genotype. How would you find its genotype ? Explain. 57/5/1 4 2 8. Q> mQ>a Ed Amby Ho$ nm Ym| H$s H$mo{eH$mAm| H$m Cn moJ H$aHo$ d km{ZH$m| Zo Eogo EH$b nm Yo Ho$ {Z m U H$m mg {H$ m {Og | Q> mQ>a VWm Amby Ho$ A{^bjU g w V $n go n[ab{jV hmoVo h & Bg H $ H$m Zm {bI H$a BgHo$ {d{^ MaUm| H$s gyMr ~ZmBE & 2 Scientists tried to develop a single plant exhibiting the characteristic of tomato and potato by using cells from tomato and potato plants respectively. Name the procedure and list the steps to achieve this. 9. (a) {H$gr Prb | N>br H$m g p Q> KZ d Amn {H$g H$ma kmV H$a|Jo ? (b) EH$ Vmbm~ | 100 |T>H$ h & EH$ df | 20 Am a |T>H$m| H$m O hmo OmVm h & Bg g p Q> H$s O Xa H$m A{^H$bZ H$s{OE & AWdm mZd g p Q> Ho$ {bE p Wa Am w {na { S> H$m AmaoI ~ZmBE & BgHo$ mam Ambo{IV (Xem E JE) g p Q> d { Xa H$s m m H$s{OE & (a) How will you measure population density of fish in a lake ? (b) In a pond there are 100 frogs. 20 more were born in a year. 2 2 Calculate the birth rate of this population. OR Draw a stable human age pyramid. Comment on the population growth rate that is depicted by it. 10. E .Amo.B .Q>r. (MOET) newAm| | gwYma H$m EH$ H$m H $ h & Bg H$m H $ Ho$ {H $ m d Z | AnZmE JE MaUm| H$mo ghr H $ | {b{IE & AWdm V ~mHy$ Ho$ Yy nmZ H$mo a VMmn | d { VWm dmV $s{V go m| g ~ {H$ m OmVm h ? m m H$s{OE & 2 2 MOET is a programme for herd improvement. Write the steps in correct sequence that are carried in the programme. OR Why is tobacco smoking associated with rise in blood pressure and emphysema ? Explain. 57/5/1 5 P.T.O. 11. {Z ZVmn n[aajU m h OmVm h ? C oI H$s{OE & ? O d-{d{dYVm Ho$ g ajU | BgH$m {H$g H$ma Cn moJ {H$ m 2 What is cryopreservation ? Mention how it is used in conservation of biodiversity. 12. S>o{dS> {Q>b Z Zo {H$g H$ma Xem m {H$ {H$gr g wXm H$m Wm{ d CgH$s Om{V m| H$s g Vm na {Z^ a H$aVm h ? m m H$s{OE & 2 How did David Tillman show that stability of a community depends on its species richness ? Explain. I S> C SECTION C 13. (a) (b) (c) EH$ amoJr H$mo m moH$m{S> b B \ $ eZ hmo OmVm h VWm CgH$s a V dm{hH$mAm| | W Ho$ nmE OmVo h & W H$m hQ>mZo Ho$ {bE W H$m $moQ>H$ Ho$ $n | Cn moJ {H$E OmZo dmbo nXmW H$m Zm {b{IE Am a Cg gy Ord H$m Zm ^r {b{IE {Oggo Bgo m V {H$ m OmVm h & EH$ r H$mo A^r-A^r d H$ mamonU h Am h & CgH$m eara Bg d H$ H$mo A drH$ma Z H$ao Bg{bE Cgo O d-g{H $ -AUw {d{e Q> Xdm Ho$ $n | {XE JE & h O d-g{H $ -AUw m h ? Cg gy Ord H$m Zm {b{IE {Oggo Bgo m V {H$ m OmVm h & C a V H$mobo Q >m b dmbo amo{J m| | a V H$mobo Q >m b Ho$ Va H$mo H$ H$aZo Ho$ {bE {M{H$ gH$ {H$g Am f{Y mam CnMma H$aVo h ? Cg moV Ord H$m Zm {b{IE {Oggo Bg Am f{Y H$mo m V {H$ m OmVm h & (a) A patient had suffered myocardial infarction and clots were found in his blood vessels. Name a clot buster that can be used to dissolve the clots and the micro-organism from which it is obtained. (b) A woman had just undergone a kidney transplant. A bioactive molecular drug is administered to oppose kidney rejection by the body. What is the bioactive molecule ? Name the microbe from which this is extracted. (c) What do doctors prescribe to lower the blood cholesterol level in patients with high blood cholesterol ? Name the source organism from which this drug can be obtained. 57/5/1 6 3 14. {Z Z{b{IV Ho$ H$maU {b{IE : 3 (a) E Q>r~m S>r p V {Vajm H$mo Vab {Vajm ^r H$hm OmVm h & (b) {H$gr amoJ Ho$ {bE ~ o H$m Q>rH$mH$aU Cgo {Vajm H $go XmZ H$aVm h (c) mZd eara | doe H$aZo Ho$ n MmV ES >g {dfmUw {H$g H$ma H$s H$mo{eH$mAm| | doe H$aVo h ? AWdm (a) {Z Z{b{IV Vm{bH$m | (i) go nhMmZ H$a {b{IE : H$maH$ Ord bjU Q >o Q>moH$moH$g (i) x amoJ H$m Zm {Z_mo{Z`m Q>mB $m BS> (ii) y (iii) amBZmodm ag Vrd da, H$ Omoar, {gaXX , Am me | nr S>m Zmgr g Hw$bVm VWm Am md, H $R>Xmh, Im gr, {gaXX z Eo Ho$[agVm Eo H$m[ag w (b) (iv) H$mo ? (iv) Cn`w V | go {H$g amoJ H$m g MaU m { H$ g dmhH$m| mam hmoVm h ? 3 Give reasons for the following : (a) Antibody mediated immunity is called humoral immunity. (b) How is a child protected from a disease for which he/she is vaccinated ? (c) Name the type of cells the AIDS virus enters after getting into the human body. OR 57/5/1 7 P.T.O. (a) (b) 15. Identify the nos. (i) to (iv) in the following table : Name of Disease Causative Organism Symptoms w Pneumonia Streptococcus (i) x Typhoid (ii) y (iii) Rhinoviruses z Ascariasis Ascaris High fever, weakness, headache, stomach pain Nasal congestion and discharge, sore throat, cough, headache (iv) Which ones of the above mentioned diseases are transmitted through mechanical carriers ? EM.E .Eg. ~rJb Zm H$ OhmO mam {g g w r {d d ^ U Ho$ Xm amZ Mm g S>m{d Z Zo {Z H$f {ZH$mbm {H$ OrdZ H$m AZwH ${ H$ {dH$mg h Am h & {Z Z{b{IV Zm| Ho$ C ma Xr{OE : (a) CZHo$ {g m V H$mo {H$g Zm go OmZVo h ? CZHo$ {g m V H$s wI {deofVmAm| H$s m m H$s{OE & (b) Cg d km{ZH$ H$m Zm {b{IE Omo Mm g S>m{d Z H$s Vah hr CgHo$ g mZ {Z H$fm] VH$ nh Mm & Charles Darwin during his famous sea voyage around the world in a ship (HMS Beagle), concluded that there has been gradual evolution of life. Answer the following questions : (a) What is his theory known as ? Explain the salient features of his theory. (b) Name a scientist who arrived at a similar conclusion as that of Charles Darwin. 57/5/1 8 3 16. H$m Ho$ XmZo H$s b ~dV H$mQ> H$m {M ~ZmBE VWm BgHo$ {H$ ht N>: ^mJm| Ho$ Zm {b{IE & 3 Draw a diagram of LS of Maize grain and label its any six parts. 17. O-a V g yh dmbr EH$ r H$m {ddmh AB-a V g yh dmbo nw f Ho$ gmW hmoVm h & g V{V Ho$ g^r g ^m{dV a $ g_yhm| Ho$ $n (\$sZmoQ>mBn) VWm OrZr $n (OrZmoQ>mBn) Xem Zo hoVw H $m g ~ZmBE & Bg H $m g _| o{jV d emJ{V Ho$ n Q>Z H$s `m `m H$s{OE & 3 A woman with O blood group marries a man with AB blood group . Work out the cross to show all the possible phenotypes and genotypes of the progeny with respect to blood groups. Explain the pattern of inheritance observed in this cross. 18. hf} Ed Mog Zo AnZm moJ VrZ MaUm| (a) g H $ U, (b) g { lU, VWm (c) AnH|$ U _| {H$ m & oH$ MaU H$s m m H$s{OE {Oggo h {g H$aZo | ghm Vm { br {H$ S>r.EZ.E. AmZwd {eH$ nXmW h & AWdm (a) S>r.EZ.E. {VH ${V Ho$db {VH ${V { emI | hr m| g n hmoVr h VWm BgH$s nyar b ~mB na EH$ gmW Zht hmoVr ? (b) {VH ${V { emI | S>r.EZ.E. H$s {VH ${V H$m g bofU EH$ b S>r | gVV Ed X gar b S>r | AgVV hmoVm h & H$maU {b{IE & 3 3 Hershey and Chase carried out their experiment under three steps : (a) Infection, (b) Blending, and (c) Centrifugation. Explain each one of these steps that helped them to prove that DNA is the hereditary material. OR (a) Why does DNA replication occur within a replication fork and not in its entire length simultaneously ? (b) DNA replication is continuous and discontinuous on the two strands within the replication fork. Give reasons. 57/5/1 9 P.T.O. 19. (a) nmofH$ JwUd mm g dY Z Ho$ {bE \$gbm| Ho$ OZZ H$mo m H$hVo h nmofH$ JwUd mm | gwYma H$s Amd H$Vm m| hgyg H$s JB ? ? (b) g yMo {d d | Mmdb, Joh VWm H$m gdm {YH$ Cn moJ {H$E OmZo dmbo Im m h & nma n[aH$ {H$ m| H$s VwbZm | BZ Im m m| H$s nmofH$Vm JwUd mm | gwYma H $go h Am ? \$gbm| H$s 3 AWdm (a) CZ moV nmXnm| Ho$ d km{ZH$ Zm {b{IE {OZgo H $ e: Amo{nAm BS >g VWm H $Zm{~Zm BS >g m V hmoVo h & (b) Zw m| | BZHo$ J mhr Wbm| H$mo {b{IE & h S >J Zw m| na H $go ^md S>mbVo h ? (a) 3 What is the breeding of crops for enhancing their nutritional value called ? Why is the need felt for enhancing the nutritional value of the crops ? (b) Rice, wheat and maize are the most commonly used food grains the world over. How have these grains improved in their nutritional value in comparison to their conventional varieties ? OR (a) Write the scientific names of the source plants from where opioids and canabinoids are extracted. (b) Write their receptor sites in the human body. How do these drugs affect the human beings ? 20. nwZ m}JO S>r.EZ.E. VH$ZrH$ | {V~ YZ E S>mo yp bE O Zo A V h dnyU ^y{ H$m {Z^mB h & nwZ m}JO S>r.EZ.E. Ho$ {Z m U | B H$mo Ama. I Ed S>r.EZ.E. bmBJo O H$s ^y{ H$mAm| H$s m m H$s{OE & Restriction endonucleases have played a very significant role in rDNA technology. Explain the roles of EcoRI and DNA ligase in formation of recombinant DNA. 57/5/1 10 3 21. S>r.EZ.E. H$mo{eH$m {P r go hmoH$a Zht Om gH$Vm (^oXZ Zht H$a gH$Vm), m| ? OrdmUw H$mo bmp _S> drH$ma H$aZo mo gj H $go ~ZmVo h ? {H$gr nmXn nanmofr H$mo{eH$m | {dOmVr S>r.EZ.E. H$mo {d Q> H$amZo Ho$ VarHo$ H$s m m H$s{OE & Cg amoJOZH$ H$m Zm {b{IE {OgH$m Cn moJ Ahm{ZH$maH$ amoJOZH$ g dmhH$ Ho$ $n | {H$ m OmVm h & 3 Why DNA cannot pass through the cell membrane ? How can the bacteria be made competent to take up a plasmid ? Explain a method for introduction of alien DNA into a plant host cell. Name a pathogen that is used as a disarmed vector. 22. g dmhH$ pBR-322 H$m {M ZrMo {X`m J`m h & BgH$m A Z H$s{OE & {M | Xem E JE A, B VWm C H$mo nhMmZ H$a {b{IE VWm {H$gr g dmhH$ H$s bmoqZJ | CZH$s ^y{ H$m H$s `m `m H$s{OE & 3 AWdm AZoH$ bmoJ AmZwd {eH$V: $nm V[aV \$gbm| H$mo drH$ma H$aZo Ho$ {bE Ame {H$V h & H$moB VrZ H$maU Xr{OE {Oggo C h| Bg H$ma H$s \$gbm| H$mo B Vo mb H$aZo Ho$ {bE Zm m Om gHo$ & 57/5/1 11 3 P.T.O. Study the figure of vector pBR322 given below. Identify A, B and C and explain their roles in cloning a vector. OR Many people are apprehensive of accepting GM crops. Give three reasons so as to convince them to use these crops. 23. mZd ewH $OZH$ Z{bH$m H$s AmaoIr H$mQ> H$m {M ~Zm H$a CgHo$ {H$ ht N>: Zm m {H$V H$s{OE & (6) ^mJm| H$mo 3 Draw a diagram of the sectional view of a human seminiferous tubule and label any six of its parts. 24. d- WmZo AWdm ~m - WmZo O d-{d{dYVm g ajU | go H$m Z-gm VarH$m A{YH$Va Om{V m| Ho$ Ap V d H$mo ~MmZo | A{YH$ ghm H$ h ? m m H$s{OE & Which one of the two in-situ or ex-situ biodiversity conservation measures help the larger number of species to survive ? Explain. 57/5/1 12 3 I S D SECTION D 25. (a) nw nr nmXn Ho$ ^ yU-H$moe H$m {M ~ZmH$a {Z Z{b{IV H$mo Zm m {H$V H$s{OE (i) Ho$ r H$mo{eH$m (ii) {Z^mJr (H $bm Ob) N>moa (iii) ghm H$mo{eH$mE : (b) Cg H$mo{eH$m H$m Zm {b{IE {Oggo ^ yU-H$moe H$m {dH$mg hmoVm h & Bg H $ H$s m m ^r H$s{OE & (c) Zm[a b | ^ yUnmof Ho$ {dH$mg H$s m m H$s{OE & 5 AWdm mZd ({ m|) Ho$ A S>me VWm J^m e | AmV d MH $ Ho$ Xm amZ nwQ>H$s md Wm VWm mdr md Wm H$s Ad{Y VWm n[aKQ>ZmAm| H$mo {b{IE & BZ Xmo md WmAm| H$mo nr yf VWm A S>me r hm m}Z {H$g H$ma ^m{dV H$aVo h ? (a) (b) 5 Draw the embryo sac of a flowering plant and label the following : (i) Central cell (ii) Chalazal end (iii) Synergids Name the cell and explain the process it undergoes to develop into an embryo sac. (c) Explain the development of endosperm in coconut. OR Write the duration and the events that occur in the ovary and the uterus during follicular and luteal phases of the menstrual cycle in humans. How do pituitary and ovarian hormones influence these two phases ? 57/5/1 13 P.T.O. 26. (a) A VaU Ama.EZ.E. (tRNA) Ho$ (b) {H$gr Agr Ho$ H$s Ho$ amB~mogmo m| | m m H$s{OE & (c) AZwboIZ w{Q> Ho$ H$maU S>r.EZ.E. Ho$ ATG Hy$Q> H$m m-Ama.EZ.E. | UAG-AZwboIZ hmo OmVm h , {Oggo amB~mogmo | {Zp H $ nm brno Q>mBS> m Ibm $nm V[aV hmoVr h & H$WZ H$m Am {M {b{IE & 1+3+1=5 Eo rZmoE{gboeZ H$m dU Z H$s{OE & m-Ama.EZ.E. H$s {dp Q> Ho$ H $ H$s AWdm {Z Z{b{IV p W{V m| | B . H$mobmB | b H$ MmboH$ (Amonoam Z) {H$g H$ma H$m` H$aVm h & `m `m H$s{OE & (a) EH$ oaH$ H$s AZwnp W{V | (b) EH$ oaH$ H$s Cnp W{V | (a) Describe aminoacylation of tRNA. (b) Explain the process that takes place in the ribosomes when mRNA makes its entry into it in a prokaryote. (c) Due to transcription error, ATG codon of DNA is transcribed into UAG in mRNA which translates a non-functional polypeptide chain in the ribosome. Justify the statement. OR Explain how does lac operon in E. coli operate (a) in the absence of an inducer. (b) in the presence of an inducer. 57/5/1 14 5 27. (a) (b) (c) nm[ap W{VH$ AZwH $ U m h ? Obma ^r AZwH $ U Ed ew H$Vma ^r AZwH $ U Ho$ EH$ g mZVm VWm EH$ {d{^ Vm {b{IE & Am { $g Am {H $S> VWm Yw Ir | n[ab{jV gh{dH$mg H $ H$s m m H$s{OE & 1+2+2=5 AWdm (a) O d-{d{dYVm j{V H$m {H$gr jo na ^md Ho$ Xmo VarH$m| H$s gyMr ~ZmBE & (b) g w{MV CXmhaUm| H$s ghm Vm go O d-{d{dYVm j{V Ho$ {H$ ht Xmo H$maH$m| H$s m m H$s{OE & 1+4=5 (a) State what is an ecological succession. (b) Write one similarity and one difference between hydrarch and xerarch sucessions. (c) Explain the mechanism of co-evolution as seen in orchid Ophrys and bee. OR (a) List any two ways the biodiversity loss affects any region. (b) Explain any two causes of biodiversity loss, with the help of suitable examples. 57/5/1 15 P.T.O.

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