Select the difference which is wrongly written Cartilaginous fish -Bony fishes
(1) Operculum is absent - Operculum is present
(2) Fertilization is internal - Fertilization is external
(3) Posses 5-7 pair of gills - Posses 4 pair of gills
(4) Mostly oviparous - Mostly viviparous

Match column I with column II and select the correct option from the gives codes. {:(A."Cartilaginous fishes",(i)"Usually external fertilisation"),(B."Bony fishes",(ii)"Internal fertilisation"),(,(iii)"Mostly oviparous"),(,(iv)"Mostly viviparous"),(,(v)"Direct development"):}

Give the answer of following questions by observatios from given figures: (i). Which fish has air bladder? (ii) which fish is known as saw fish? (iii) which fish is cartilaginous fish? (iv). Which animal is ectoparasite on true fishes? (v) Which fish has paired fins? (vi) which fishh has body skeleton? (vii) Which fish has 4-pairs of gills? (viii) Whch fis has operculum? (ix) Which fishes are viviparous? (x) Which fish lives in fresh water?

Chemical bonding between two atoms is necessarily associated with an electrical moment arising out of the difference in electroegativity of two atoms. This means that every bond carries with it an electrical moment called the ''bond moment''. The dipole moment of a molecule is really the vectorial sum of the individual bond moment present in it. To compute the dipole moment it is necessary to find out the values of various bond moment. In the following table, dipole moment of different bonds are as given. {:(,rarr,rarr,rarr),("Bond",H-C,C-Cl,C=0),("Bond moments",0.4 D,1.5 D,2.5 D):} The group moments of few groups as given {:("Group",NO_(2),OH,CN,CH_(3)),("Direction of dipole","Towards N","Towards O","Towards N","Away from "CH_(3)),("Dipole moment",4D,1.6D,3.8D,0.4D):} The bond angle in H_(2)S is 97^(@) and its dipole moment is 1.5 D. The S-H bond distance is 0.15 nm. Therefore, approximate percentrage ionic cjaracter pf S-H bond is (neglect the effect of dipole moment of lone pair on sulphur atom in H_(2)S ). (Given : [cos 97^(@)=-0.121 and sqrt(0.88)=0.94] )

Consider the following characteristic of fishes :- (1) They have four pairs of gills which are covered by an operculum. (2) They have air bladder which regulates buoyancy (3) They are mostly viviparous and development is direct (4) Their body is streamlined and covered with cycloid/ctenoid scales Which of the above characteristics regarding bony fishes are correct?

How many pairs of letters are there in the word OPERATION in which the difference between them is same as in the English alphabet? 1) Nine 2) Seven 3) Five 4) Eight 5) None of these

Counting numbers have fascinated human mind from time immemorial. The first set he seems to have pondered about is the set of natural numbers, N Various subsets of this set were diffined. Note worthy among them are Prime Number :- if a natural number has exactly tow divisors it is called a prime number. Yet another way Simple examples are 2,3,5,7,........... {2,3} in the only set of consective primes. Composite numbers :- A natural number habing more than 2 divisors is called a composite number. Simple examples are 4,6,8,9,10,.......... Note that 1 is neither prime nor composite. Coprime or relatively prime numbers :- A pair of natural numbers is acalled a set of coprime numbers if their highest common factor (HCF) or greatest common divisor (g.c.d.) is 1. For example 8 & 5 are co-prime Note that these two numbers need not be prime. More over 1 is coprime with evert natural numbers. a prime number is coprime with all natural numbers which are not it's multiple. Twin Prime :- A pair of primes is called twin primes if their non-negative difference is '2' For example {3,5} , {5,7}, (11,13} , ......... Based on above difinitions solve that following problems Number of composite numbers less than 15 is