What are the actions that cause a Muslim to fall into apostasy from Islam?

God has obligated Muslims to adhere to Islam and warned against the causes of apostasy and polytheism. Scholars have mentioned that the nullifiers of Islam are ten:

1. Shirk (polytheism) with Allah in worship. 2. Taking intermediaries to supplicate Allah and seek intercession. 3. Not declaring polytheists as disbelievers, or doubting their disbelief, or affirming their doctrine. 4. Believing that a guidance other than that of the Prophet is more complete than his guidance, or that a ruling other than his is better than his ruling. 5. Hating anything that the Messenger brought. 6. Mocking anything from the religion of the Messenger, or its rewards, or its punishments. 7. Sorcery. 8. Supporting polytheists and assisting them against Muslims. 9. Believing that some people are permitted to deviate from the Sharia of Muhammad, peace and blessings be upon him. 10. Turning away from the religion of Allah, neither learning it nor acting upon it.

There is no difference in these nullifiers between one who is joking, serious, or fearful, except for one who is coerced.

Also included in the fourth point is believing that man-made systems and laws are better than the Sharia, or equal to it, or that it is permissible to resort to them for judgment, or that the Sharia is not suitable for the present age.

And whoever deems permissible what Allah has forbidden, which is known by necessity to be from the religion, is a disbeliever by the consensus of Muslims.