Final answer:
The critical activity in political and civic life that informs the public about injustices and prompts democratic action is Journalism, which includes becoming a citizen journalist.
Step-by-step explanation:
The type of activity that is very important in political and civic life, providing awareness to people of unjust events across the world and leading to public pressure on governments for action, is Journalism. Individuals can engage in a democratic society not only through voting and participating in protests but also by engaging in activities such as advocating for change, using social media to track and communicate with elected representatives, and becoming a citizen journalist. By documenting and sharing information on local government and politics, citizens can influence public policy and increase transparency, highlighting the importance of democratic participation and free speech in effecting change.