dyscalculia: impaired ability to learn grade-appropriate mathematics
learning disorder: a disorder found in children of normal intelligence who have difficulties in learning specific skills
eutrophication: excessive nutrients in a lake or other body of water, usually caused by runoff of nutrients (animal waste, fertilizers, sewage) from the land, which causes a dense growth of plant life; the decomposition of the plants depletes the supply of oxygen, leading to the death of animal life