Answer: D) All the above Explanation: Intermolecular forces : The forces of attraction present in between the molecules or atoms or compounds is termed as intermolecular forces. The molecule HCl is composed of hydrogen and chlorine atom. There is high difference in electronegativities therefore, it is polar in nature. The H end of HCl is permanently slightly positive charge. The Cl end of HCl has a permanent slight negative charge. the "H" in one molecule is attracted to the "Cl" in a neighbor. The intermolecular force is weak compared to a covalent bond. But this dipole-dipole interaction is one of the stronger intermolecular attractions. It also has hydrogen bonding and dispersion forces.  Dispersion forces are the weakest forces which are present in between all molecules or atoms.Hydrogen bonds are present in molecules having at least one H-A bond where A is the strong electronegative atom (mainly F, Cl and N).

Answer: B) Respirometer Explanation: A respirometer is a device used to measure the rate of respiration of a living organism by measuring its rate of exchange of oxygen and/or carbon dioxide.

90 D in RA means 90 Degrees in Right Angle. It is a logic question which is to be eloborated.   Some more of its kind are: 1. 52 W in a Y     -    52 Weeks in a Year 2. 7 C in a R        -    7 Colours in a Rainbow 3. 9 P in SS 4. 5 C in an OF 5. 12 S of the Z

Implied powers are powers of U.S. government which have not been explicitly granted by the Constitution but that is implied by the necessary and proper clause to be delegated for the purpose of carrying out the enumerated powers.

5 L from A are V means 5 Letters from Alphabet are Vowels.   Some more of that are: 1. 7 W of the W  :  7 wonders of the world. 2. 5 T on a F       :   5 toes on a foot. 3. 12 S of the Z   : 12 signs of the zodiac. 4. 90 D in a R A 5. 9 P in SS

Answer: D) 10 Explanation: Let Rajeev's present age be  x years. Rajeev's age after 15 years = (x + 15) years. Rajeev's age 5 years back = (x - 5) years Then ATQ,  x + 15 = 5 (x - 5) x + 15 = 5x - 25 => x = 10   Hence, Rajeev's present age = x = 10 years.

Answer: B) Electron transport chain Explanation:

Answer: C) 21 Explanation: A prime number is a whole number greater than 1 whose only factors are 1 and itself.   Factors of 5 are 1, 5 Factors of 11 are 1, 11 Factors of 21 are 1, 3, 7, 21 Factors of 37 are 1, 37.   Hence, according to the definition of a prime number, 21 is not a prime number as it has more than two factors.