Science doesn't assign such "responsibilities".
I try to make it simple.
- 1. the Sun emits light
- 2. Earth rotates around poles axis
While you are on the lighted part of Earth surface, it's day.
The rest of the time you are in the shadow: it's night
- 3. the Moon doesn't emit light but reflects Sun light
- 4. the Moon doesn't emit "dark" either! so is not "responsible" for night
- 5. the Moon orbits Earth
So the Moon can be in your part of sky either at night or during the day. But you mostly notice its dim reflected light at night in a dark sky or sometimes near to dawn and dusk.
Depending on relative positions of Sun, Earth and Moon, the shape of the lighted part of the Moon can go from full disk ("Full Moon") to thick or thinner crescent and even nothing ("New Moon")
- 6. like the moon, Venus doesn't emit light but reflects Sun light.
The light reflected by Venus is brighter than any star in our sky (besides the Sun of course)
- 7. like Earth Venus orbits the Sun, but closer than Earth.
So Venus is also close to the Sun when observed from Earth.
Most of the time when bedazzled by the Sun, you cannot see it.
You can only see Venus when the Sun is under the horizon and Venus just above, either before sunrise or just after sunset.
In this case Venus is the only one bright spot in the sky