if you don't know the answer to one of the problems you can just answer how every many you know and btw ill mark you!!

Answer:
#2 is correct.
#3 is correct, mammals are vertebrates, which means cows counts, also frogs, since they have to jump a lot, they have 10 vertebrae. Also, hawks, since they're vertebrates, and all vertebrates have backbones.
$4 is correct.
If you like my answer, please mark me brainliest.