BPGHS_2018_Bio_Prelim_ANS.pdf

©BPGHS 2018 6093 / SEC 4 EXP BIO PRELIM / P1 / 18 [Turn over ANSWERS 1. C 2. B 3. C 4. C 5. B 6. C 7. B 8. C 9. C 10.C 11.C 12.B 13.D 14.D 15.A 16.A 17.C 18.B 19.A 20.B 21.C 22.C 23.C 24.C 25.A 26.D 27.C 28.A 29.B 30.A 31.C 32.B 33.A 34.D 35.C 36.D 37.D 38.C 39.A 40.C www.KiasuExamPaper.com C 18. B 191111. A 2020200200020002020020222222.. B 212121111211111111. CCCCCCCCCCCCCC 22. CCCCCCCCCCCCCCCCCCCC 2323232323232223232232323232223232223232323222233333333. CCCCCCCCCCCCCCC 24424424242424242424242424242424224224222442444444444444444. C 25252222522252522252252525252525252522522225225252225525255525525555555.................... AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA 2626262622226222222626222262622622662266222626266662662. DDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDD 27272727272727272727272727272727727272772772222222. CCCCCCCCCCCCCCCCCCCCCCCCC 28.. AA 2929. BB 30. A 94

18 ©BPGHS 2018 6093 / SEC 4 EXP BIO PRELIM / P2 / 18 [Turn over Q ANSWERS SECTION A mark 1a Filament correctly labelled; Sepal correctly labelled 1 1 b Any two of: -l a r g e p e t a l s -n e c t a r / n e c t a r g u i d e s -b r i g h t l y - c o l o u r e d 2 ci Anthers + pollen grains made and released Stigma+l a n d i n go f p o l l e n g r a i n s(A: catch ; R: transfer) Ripen/ Mature at different times No transfer of pollen within the flower A:stigma situated above the anthers R: stigma is located far from the anther ½ ½ ½ ½ cii Insect/bee lands on flower/petals Reaches for/to get the nectar (R: while eating nectar – it is the act of getting the nectar that dislodges the pollen) Hits stamens/anthers Pollen onto his backAW/carries pollen/ref. flower of same species Hits style/stigma Stigma collects pollenfrom bee’s back/ pollen falls onto the stigma Correct ref. older/younger flowers/ref. cross pollination/to other flower ½ ½ ½ ½ ½ ½ ½ [max 3] 2a Codominance / codominant 1 b Child 6 Group O and Group B parents unable to pass down the IA allele OR There is no IAallele in either parent 1 1 c Parental genotypes: IBIO X IBIO Gametes: IB, IO, IB, IO Offspring genotypes: IBIB IBIO IOIO Offspring phenotypes: Group B and Group O ½ ½ ½ ½ 3a Less water near soil surface Less water for photosynthesis Less carbohydrate manufacture Less waterfor salts to be absorbed/dissolve/in cell sap Less proteins made Roots too short to reach water More herbivores eat grass Trees can lose leaves in times of stress ½ [2 max] b More food / vegetation in abundance Different types of habitat Less competition ½ each [1 max] c Longer necks Fewer of them ½ ½ d More foliage found higher up / have to eat leaves Mutation Those with shorter necks die / do not breed Natural selection ½ each [1 max] 4a Cleaner (ie. less particulate matter) at near body temperature (A higher temperature/warmer) More carbon dioxide less oxygen more moisture (A saturated);;; A: cleaner R: high pressure 3 b External intercostal muscles relax Internal intercostal muscles contract Diaphragm