So, imagine you have a really big bathtub. And in that bathtub, there's a part that's more like a flat surface that's not as deep as the rest of the tub. That flat part is kind of like the "continental shelf" of the tub.
Now, Russia is a very big country with a lot of land that goes all the way up to the Arctic Ocean. And just like the bathtub, Russia has a continental shelf too! It's a big area of land under the water that's not as deep as the rest of the ocean, and it stretches out pretty far from the shore.
The continental shelf of Russia is really important because it has a lot of natural resources like oil, gas, and minerals that can be extracted from the ground. There are also a lot of fish and other sea creatures that live in that area, which can be caught for food.
Russia is really protective of their continental shelf because it gives them access to all those resources and helps their economy. They've even made claims to expand their continental shelf farther out into the Arctic Ocean, so they can try to get even more of those resources.