The reason why there is a green layer of algae was because
of the reason that there may be too much fertilizer applied in the lawn. When
having too much fertilizer, and it had been rained down—there could have been a
possibility of run-off to be flown down on the lawn of which has been sloped
and made its way on the pond. By this, it increases the nutrients in the pond,
making the algae to grow on it.
What kind of model there is many kinds
Galaxy, solar system, star, planet, moon
From Pollution you know smokes
B. are trying to use the same resources