Can someone tell me the answer plz i’ll give you brainlist and points

a. a primary source combines several different accounts of an event. b. a primary source generally benefits from having been written after an event.

explanation:

5 structural isomers

the isomers are:

n-exane :   ch3ch2ch2ch2ch2ch3

2-methylpentane :   ch3ch(ch3)ch2ch2ch3

3-methylpentane :   ch3ch2ch(ch3)ch2ch3

2,3-dimethylbutane :   (ch3)2chch(ch3)2

2,2-dimethylbutane :   (ch3)3cch2ch3