Answer:
The correct answer would be:
                   A         G          C         T
Human:    31          19          19       31
Cow:         28         22      22         28
Salmon:     29       21        21         29
Wheat        27      23        23        27
Yeast         31         19       19         31
Explanation:
According to the rule of Chargaff which states or explains the amount of the A, T, G, and C bases in the DNA molecule. It says that the DNA of any organism should have a pyrimidine and purine ratio of 1:1. This means the amount of A would be equal to T and the amount G should be equal to the amount of C.
 It also says that the amount of a and G would be equal to the amount of C and T. So on the base of this we can find the missing value in the table:
                     A         G          C         T
Human:    31          19          19       31   (A= T and G=C)
Cow:         28         22      22         28  (A= T and G=C)
Salmon:     29       21        21         29   (A= T and G=C)
Wheat        27      23        23        27 (100 - A+T = G+C)
Yeast         31         19       19         31 (A= T and G=C)