Magnetic field lines form closed loops:. a) Around and through bar magnets.
b) Through current-carrying loops.
c) Around current-carrying straight wires.
d) All of the above.

d) All of the above.

Explanation:

Magnetic field lines are formed around an object when there is a magnetic field around the object. From the question, we know that a bar magnet has an electric field. A current carrying loop has a magnetic field around it also. Current carrying straight wires and any conductor generally, carrying an electric current, produces a magnetic field around them. This magnetic field has lines of loos formed close to the material.

depends on what you mean by "group." for order, it would be coleoptera (beetles). for class, it would be insecta (insects). for phylum, it would be the arthropoda (animals with jointed exoskeletons).

explanation:

yup its correct its: c) b b