Answer: One advantage is, well, the water. There’s plenty of it and it’s all around. Therefore, most aquatic plants do not need adaptations for absorbing, transporting, and conserving water. They can save energy and matter by not growing extensive root systems, vascular tissues, or thick cuticles on leaves. Support is also less of a problem because of the buoyancy of water. As a result, adaptations such as strong woody stems and deep anchoring roots are not necessary for most aquatic plants.
Natural selection is when certain environmental qualities cause a species to evolve in order to survive in the environment. Natural selection is a specific part of that, when some of the variations of the species die off because they can't survive, then the ones who survive live to create more living babies with the qualities that allow them to survive in the environment.
Brain. :) that's your answer haha