They do the same job as terrestrial plants. They anchor the plant and keep it in place and they collect food (NPK and many other trace elements) which they send into the plant to enable it to photosynthesize and transpire in other words grow.
Roots
the use it to absob water and minerals from the soil
Do get water, and vitamins and minerals from the soil and from the fertilizer you may use.
They use their roots to reach ground water, and use that water for photosynthesis.
most plant use there roots to absorb water from the earth or soil but some plants use their leaves to catch water.
Carbon dioxide is present in water from fish respiration and the breaking down of organics such as rotting leaves. As far as how they assimilate it, it's pretty much the same as terrestrial plants. Absorbsion through their leaves, roots, etc.
You must play on to unlock them, or use a lily pad to place land plants on water. They will be eaten separately.
Marine is used as an adjective when it is describing something found in or produced by the sea. (Example: marine life, marine plants) Aquatic is of or relating to water. (Example: aquatic sports, aquatic animals, aquatic plants)
Do get water, and vitamins and minerals from the soil and from the fertilizer you may use.
plants can absorb water through tiny pores in their roots. i dont know what the pores are called though. they also gain water by their leaves through holes which are called stroma, this is a gap in the leaf, and is surrounded by Guard Cells.
Photosynthetic plants are plants that use photosynthesis, or the process of turning sunlight into sugar, for engergy.
Because they are plants, the roots are used the same way in cacti as in every plant, to take in water for the plant to use.