if an animal is a vertibrate, then it has a spinal column

Answer 1

You don't tell us what the question is, but let's examine this statement:

Having a spinal column is the definition of being a vertebrate animal. Therefore, this statement could be written as a biconditional ("if and only if"). An animal is a vertebrate if and only if it has a spinal column.

It would also be fair to say that the converse is true, right? If an animal has a spinal column, then it is a vertebrate.

How about the inverse? If an animal is not vertebrate, then it does not have a spinal column.

And finally, how about the contrapositive? If an animal does not have a spinal column, then it is not a vertebrate.

I think you are to infer from this that if a statement is a biconditional, then all the other logical forms given here will also hold true.

Best wishes!