Which of these devices is a type of aerobic exercise machine?

Treadmills are the most popular type of aerobic equipment both at home and in gyms. Walking or running on a treadmill can strengthen your lower body and improve cardiovascular conditioning.

Explanation:

a.metals can become magnetic if they have many spinning electrons that create magnetic fields.d.only some metals are attracted by magnets; these metals are called ferromagnetic.

d.wrapping an insulated wire around a metal with ferromagnetic properties and applying an electric current.

answera compound;