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- Standard 12
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Given below are four statements $(A-D)$ each with one or two blanks. Select the option which correctly fills up the blanks in two statements. Statements :
$(A)$ Wings of butterfly and birds look alike andare the results of ___$(i)$___ evolution.
$(B)$ Miller showed that $CH_4 , H_2 , NH_3$ and ___$(i)$___ when exposed to electric discharge in a flaskresulted in formation of ___$(ii)$___ .
$(C)$ Vermiform appendix is a ___$(i)$___ organ and an ___$(ii)$___ evidence of evolution.
$(D)$ According to Darwin evolution took placedue to ___$(i)$___ and ___$(ii)$___ of the fittest.
$(D) -(i)$ small variations, $(ii)$ survival,
$(A) -(i)$ convergent
$(A) -(i)$ convergent,
$(B) -(i)$ oxygen, $(ii)$ nucleosides
$(B) -(i)$ water vapour, $(ii) $ amino acids, $(C) -(i)$ rudimentary, $(ii)$ anatomical
$(C) -(i) $ vestigial, $(ii)$ anatomical,
$(D) -(i)$ mutations, $(ii) $ multiplication
Solution
(a) : Binocular vision, smaller jaw and upright posture are the main adaptations that led to evolution of man from its ancestors. But, during human evolution major and most significant changes occurred in the cranial capacity ofman. In living modern man it is about $1450 \ cc$ compared to $500\ cc$ in Australopithecus. Increased cranial capacity accommodates larger brain and forms the basis of social, cultural and educational evolution of modern man.
