Brown-green algae refers to mainly one celled plants called diatoms. Diatoms are a major component of the oceans. Diatoms are important because they are at the start of the the food chain for many protozoa.  The abundance of oil droplets within their structure and time are responsible for many deposits of oil.

Brown-red algae refers to large plants of the sea, including kelp and seaweed. Plants in the marine environment do not need the elaborate system of getting nutrients to all parts of their bodies, because the marine environment has all these nutrients available. However, marine plants must develop a way to rid themselves of salt.

Green algae refer to both marine and freshwater aquatic plants.  Some are microscopic others are   They all contain

seaweed exposed at low tide	filamentous green algae

Bryophyta which includes mosses and liverworts are mainly inconspicuous plants growing in moist habitats. They are not fully adapted to life on land because they need water to reproduce. Bryophytes do not get very large.

habitat for moss - wet	moss growing on vascular plants