Eat nothing but Kelp for 3 days.

Power a Furnace with Lava.

Trade with a villager at the build height limit

Free fall from the top of the world (build limit) to the bottom of the world and survive

Build a tower of Scaffolding that reaches the maximum build height.

Swim in lava while having the Fire Resistance effect.

Stay underwater for one full day without using potions.

Travel by minecart to a point at least 500m in a single direction from where you started.

Use a Grindstone to get experience from an enchanted item.

Cure a zombie villager.

Stay underwater for 2 minutes.

Relieve a Blaze of its rod.

Deal nine hearts of damage in a single hit.