Because they are thicker making it hard for light to travel through
Some clouds are darker because of the lack of sunlight. Some clouds are blocking the other clouds and it forms a shadow and that the cloud won't get sunlight. Also that if the cloud is darker, because it is pollution. Pollution is like an evil dye that no one likes because it also has a lot of chemicals in it. That is why NEVER DRINK RAIN WATER! The darker clouds have water (rain) in them, where as the white ones are just empty.
they are not.
Because of shadows made by craters.
This shade is noticeably darker than the other.
Other way around
They are colder and darker than the other areas
They are features that are darker than other features such as if you were in a cave and the far side is darker than the other side than that is the low level image feature. ( they can be in any rainforest and in any caves or oceans.)
There is "In seventh heaven."
Lighter colors reflect some heat while darker colors absorb it.
Topsoil is darker than other layers of soil because it contains a higher concentration of organic matter like decomposed plant material. This organic matter adds nutrients and helps retain moisture in the soil, which contributes to its darker color.
If your asking than the windows are darker than other windows.
Some parts of the ocean appear darker than others due to differences in the amount of sunlight that penetrates the water. Deeper areas or regions with more particles and organisms can absorb or scatter light, making the water appear darker.