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1. Choose the most correct answer. Question i.Molecular solids are(a) crystalline solids(b) amorphous solids(c) ionic solids(d) metallic solidsAnswer:(b) amorphous solids Question ii.Which of the following is n-type semiconductor?(a) Pure Si(b) Si doped with As(c) Si doped with Ga(d) Ge doped with InAnswer:(b) Si doped with As Question iii.In Frenkel defect(a) electrical neutrality of the substance … Read more

1. Multiple choice questions Question 1.Observe the graph and select the correct option.(a) Line A represents, S = CA²(b) Line B represents, log C = log A + Z log S(c) Line A represents, S = CAZ(d) Line B represents, log S = log Z + C log AAnswer:(c) Line A represents, S = CAZ … Read more

1. Multiple choice questions Question 1.Which one of the following has the largest population in a food chain?(a) Producers(b) Primary consumers(c) Secondary consumers(d) DecomposersAnswer:(a) Producers Question 2.The second trophic level in a lake is ……………………(a) Phytoplankton(b) Zooplankton(c) Benthos(d) FishesAnswer:(b) Zooplankton Question 3.Secondary consumers are …………………….(a) Herbivores(b) Producers(c) Carnivores(d) AutotrophsAnswer:(c) Carnivores Question 4.What is the % … Read more

1. Multiple choice questions Question 1.Which factor of an ecosystem includes plants, animals, and microorganisms?(a) Biotic factor(b) Abiotic factor(c) Direct factor(d) Indirect factorAnswer:(a) Biotic factor Question 2.An assemblage of individuals of different species living in the same habitat and having functional interactions is ……………….(a) Biotic community(b) Ecological niche(c) Population(d) EcosystemAnswer:(a) Biotic community Question 3.Association between … Read more

1. Multiple choice questions Question 1.MU The bacterium which causes a plant disease called crown gall is ………………..(a) Helicobacter pylori(b) Agrobacterium tumifaciens(c) Thermophilus aquaticus(d) Bacillus thuringienesisAnswer:(b) Agrobacterium tumtfaciens Question 2.The enzyme nuclease hydrolyses ……………….. of polynucleotide chain of DNA.(a) hydrogen bonds(b) phosphodiester bonds(c) glycosidic bonds(d) peptide bondsAnswer:(b) phosphodiester bonds Question 3.In vitro amplification of DNA … Read more

1. Multiple choice questions Question 1.Antibiotic Chloromycetin is obtained from ………………….(a) Streptomyces erythreus(b) Penicillium chrysogenum(c) Streptomyces venezuelae(d) Streptomyces griseusAnswer:(c) Streptomyces venezuelae Question 2.Removal of large pieces of floating debris, oily substances, etc. during sewage treatment is called ………………….(a) primary treatment(b) secondary treatment(c) final treatment(d) amplificationAnswer:(a) primary treatment Question 3.Which one of the following is free … Read more

1. Multiple Choice Questions Question 1.Which of the following is NOT caused by unsterilized needles?(a) Elephantiasis(b) AIDS(e) Malaria(d) HepatitisAnswer:(a) Elephantiasis Question 2.Opium derivative is …………………(a) Codeine(b) Caffeine(c) Heroin(d) PsilocybinAnswer:(c) Heroin Question 3.The stimulant present in tea is …………………(a) tannin(b) cocaine(C) caffeine(d) crackAnswer:(c) caffeine Question 4.WhIch of the following Is caused by smoking?(a) Liver cirrhosis(b) Pulmonary … Read more

Question 1.The nervous system of mammals uses both electrical and chemical means to send signals via neurons. Which part of the neuron receives impulse?(a) Axon(b) Dendron(c) Nodes of Ranvier(d) NeurilemmaAnswer:(b) Dendron Question 2.……………. is a neurotransmitter.(a) ADH(b) Acetyl CoA(c) Acetylcholine(d) InositolAnswer:(c) Acetylcholine Maharashtra Board Class 12 Biology Solutions Chapter 9 Control and Co-ordination Question 3.The … Read more

1. Multiple choice questions Question 1.The muscular structure that separates the thoracic and abdominal cavity is …………………..(a) pleura(b) diaphragm(c) trachea(d) epitheliumAnswer:(b) diaphragm Question 2.What is the minimum number of plasma membrane that oxygen has to diffuse across to pass from air in the alveolus to haemoglobin inside a R.B.C.?(a) two(b) three(c) four(d) fiveAnswer:(a) two Question … Read more

1. Multiple choice questions Question 1.The muscular structure that separates the thoracic and abdominal cavity is …………………..(a) pleura(b) diaphragm(c) trachea(d) epitheliumAnswer:(b) diaphragm Question 2.What is the minimum number of plasma membrane that oxygen has to diffuse across to pass from air in the alveolus to haemoglobin inside a R.B.C.?(a) two(b) three(c) four(d) fiveAnswer:(a) two Question … Read more