Final answer:
The incorrectly paired option is XX, cow. In mammals, it's XX for females and XY for males. The other listed mechanisms are correctly paired for their respective species.
Step-by-step explanation:
For the mechanisms of sex determination, the incorrectly paired option is: XX, cow. In mammals, sex is determined by the presence of XX (homozygous) in females and XY (heterozygous) in males. The other options listed, XO in grasshoppers, ZW in bluebirds, and environmental factors such as temperature influencing sex determination in alligators, are correctly paired sex determination systems in those respective species.
In birds, sex determination is dependent on Z and W chromosomes, with ZZ being homozygous resulting in a male and ZW being heterozygous resulting in a female. This system is the opposite of the mammalian system, where the presence of a Y chromosome determines male sex.