What happens when we keep plants in the dark?

In the absence of light, plants shed their leaves and die, leaving only their roots and stems. Plants grow slowly at night and in winters. Most animals are also dependent on light, although some have adapted to their dark habitats. For example, the moles living below the ground are almost blind because they do not need their eyes underground. We humans also need sunlight to help produce vitamin D in our skin, which in turn is needed for building bones. We will also lose the perception of time if it is pitch dark around us for very long.