Answer: B) 360 Explanation: There are 7 digits 1, 2, 0, 2, 4, 2, 4 in which 2 occurs 3 times, 4 occurs 2 times.    Number of 7 digit numbers = 7!3!×2! = 420   But out of these 420 numbers, there are some numbers which begin with '0' and they are not 7-digit numbers. The number of such numbers beginning with '0'.   =6!3!×2! = 60   Hence the required number of 7 digits numbers = 420 - 60 = 360

Answer: A) Lose electrons and forms cations Explanation: When combining with nonmetallic atoms, metallic atoms generally will Lose electrons and forms cations.   As the ionization energy of te metals are very low, so they can easily lose electrons and form positively charged ion called cations.

Answer: A) सेल स्पष्टीकरण: एक स्प्रेड शीट में एक कॉलम और एक पंक्ति के प्रतिच्छेदन को सेल या बोन कहा जाता है।