These days, most drains are made with PVC or ABS plastic. Plastic drain fittings are usually glued, but the ones you might need to remove temporarily, like cleanout plugs, are threaded.

Scrape off the old wax ring from the flange, toilet base, and floor using a putty knife. Inspect the flange for cracks, rust, ...

from guttering along the roofline to drains in kitchens and bathrooms. Most of the time PVC goes unnoticed, but if there's a problem, you'll want to remove glued PVC fittings and repair or replace ...