Imagine a forest where many animals live and make different sounds. During the day, you can hear birds singing happily in the trees. There's a giant moose walking slowly and munching on soft green grass. Nearby, squirrels are busy searching for cones to eat and store for later.
But when the sun sets and it's nighttime, the forest changes! You might hear frogs croaking loudly near a pond. And watch carefully, a sly lynx comes out to hunt quietly in the dark.
This shows how the forest is alive all day and night, with different animals being active at different times!