What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all z, if z drives a car, then z is taking a plane. There is at least one z for which z is a scientist if and only if z will drive a car. For all z, z will take a plane if and only if z is a scientist.
For all z, if z takes a plane, then z is a scientist. There is at least one z for which if z were a scientist, then z is driving a car. For all z, if z were a scientist, then z is taking a plane. There is at least one z for which if z drives a car, then z is a scientist.