The theme for International Mother Earth Day, 2021 was ‘_______’.

The correct answer is Restore our Earth.

International Mother Earth Day (also commonly known as Earth Day) is celebrated annually on April 22 to raise awareness about environmental protection and conservation. Each year, a specific theme is designated to focus global attention on a pressing environmental issue.

The theme for International Mother Earth Day 2021 was "Restore our Earth". This theme focused on natural processes, emerging green technologies, and innovative thinking that can restore the world's ecosystems, rather than just adapting to or mitigating the damage already done.

Let us look at the timeline of other themes listed in the options:
- "Protect our Species" was the theme for Earth Day 2019.
- "Climate Action" was the theme for Earth Day 2020 (marking its 50th anniversary).
- "End Plastic Pollution" was the theme for Earth Day 2018.