Why are algae and ferns both green?

Hello. This question is incomplete. The full question is:

"Why are algae and ferns both green?  They each contain chlorophyll that absorbs violet-blue light and reflects green light.  They each contain chlorophyll that absorbs green light and reflects violet-blue light.  Algae contain chlorophyll, and ferns contain ferredoxin that absorbs violet-blue light and reflects green light.  Ferns contain chlorophyll, and algae contain ferredoxin that absorbs green light and reflects violet-blue light."

They each contain chlorophyll that absorbs violet-blue light and reflects green light.  

Explanation:

Chlorophyll is the pigment present in all vegetables. This is a natural pigment responsible for the color that we visualize in the plant. There are several different types of chlorophyll, however the most common is the one that absorbs blue violet light and reflects green light, allowing us to be able to visualize plants in green.

Chlorophyll can be seen in other organisms, in addition to plants, like algae, for example.

Often the plants have other colors and not green. These planats contain chlorophyll, but they also contain substances that modify the natural pigment of chlorophyll.