Answer: A) Parvovirus B19 causes severe anemia because it preferentially infects erythrocyte precursors Explanation: Parvovirus B19 causes severe anemia because it preferentially infects erythrocyte precursors.   a. Parvovirus B19 binds preferentially to the erythrocyte blood group P antigen on erythroid precursor cells. Answers B, C, D are incorrect: b. after entry the single-stranded viral DNA genome is transported to the cell nucleus where the host DNA polymerase synthesizes the complimentary DNA strand. c. Parvovirus B19 infection can be diagnosed by direct detection of viral DNA not RNA. d. the fetus of a seropositive mother is protected from infection by maternal circulating antibodies.

Answer: A) nonpolar, with a symmetrical distribution of charge Explanation: CF4 is tetrahedral. Since the four 'F' atoms have the same electronegativity values, there is no bias in electron distribution toward any one.   Therefore, electron/charge distribution is symmetrical, which also means that the molecule is nonpolar.   Hence, CF4 is nonpolar molecule with a symmetrical distribution of charge.

Answer: A) 5 kmph Explanation: Let p be the speed of man in kmph According to the given data in the question, Distance travelled by bus in 10 min with 20 kmph == Distance travelled by man in 8 min with (20 + p) kmph in opposite direction => 20 x 10/60 = 8/60 (20 + p) => 200 = 160 + 8p => p = 40/8 = 5 kmph.

Answer: A) 15:07 hrs Explanation: Next train comes at 17:00 hrs.So, last train will be = 17:00hrs - 2:30hrs= 14:30hrsAnnouncement made after 37 min of the last train.S0, 14:30hrs + 00:37 min= 15:07 hrs.

Answer: B) 60 Explanation: The given digits are 1, 2, 3, 5, 7, 9   A number is even when its units digit is even. Of the given digits, two is the only even digit.Units place is filled with only '2' and the remaining three places can be filled in ⁵P₃ ways.   Number of even numbers = ⁵P₃ = 60.

Answer: D) 51 Explanation: Unit digit of this expression is always 1 as the base ends with 1.  For the tenth place digit we need to multiply the digit in the tenth place of the base and unit digit of the power and take its unit digit. i.e, tenth place digit in 2151 is 5 and tenth place digit in power 415 is 1 And the units digit in the product of 5 x 1 = 5   Therefore, last two digits of 2151415 is 51.

Answer: D) the capacity of layers of metal ions to slide over the other Explanation:

Answer: D) 15,200 Explanation: Ratio of investment of all the three members = (7 x 12) : (9 x 12) : (2/3 x 9 x 6) = 7 : 9 : 3 Given Rushi's one year profit = Rs. 5600 => Let the total profit = Rs. P Then, P x 7/19 = 5600 Total profit P = 19 x 5600/7 = Rs. 15,200.