Step 1: The progestin-only pill works through several contraceptive actions, so we should check each listed effect.
Step 2: By making cervical secretions thick and hostile, it blocks sperm from ascending into the uterus, satisfying the cervical mucus effect.
Step 3: It additionally suppresses ovulation and renders the endometrium thin and atrophic, so a fertilized ovum cannot implant. These cover the ovulation and uterine lining effects.
Step 4: Because every individual statement is a genuine action of the minipill, the combined choice is correct.
\[\boxed{\text{All of the above}}\]