21.

NaCl has ionic bond because

• Both Na and Cl has same number of valence electron

• Both Na and Cl belongs to same group

• Na loses one elctron and chlorine receives one electron

• Due to difference in their electronegativity

Brown ring test is confirmatory test for which anionic species?

• Nitrate

• Bromide

• Chloride

• Fluoride

The graph below shows frequency distribution of different sizes of cell during different stages of cell culture.

From this pattern of growth we can draw conclusion that

• Most of the cell divides at same time

• Rate of cell division is constant

• Cell does not divide

• All the cell divides at same time

The computer codes for decimal number 99 will be

• 1100011

• 1110111

• 1000011

• 011000111

Parts per billion can be represented as :

• ng/ Kg

• μg/ Kg

• μl/ l

• μg/ g

Which of the following is not possible in biological systems?

• DNA → RNA → Protein

• Protein → RNA → DNA

• Glucose → Amino acid → Proetin

• RNA → DNA → Protein

The liquid is flowing in tube as shown in diagram :

The rate of flow at position A as compare to B will  be

• four times

• sixteen times

• half

• one-fourth

Which is not a structural alignment tool?

• SSAP

• TM-align

• T-coffee

• DALI

Which of the following is major radioactive indoor air pollutant in home air conditioner?

• Cs

• U

• Sr

• Rn

Variation in two characters in two or more species can be best represented by

• Histogram

• Scattered diagram

• Triangular box

• Linear curve