What is the predicted sand dollar population in a 30m2 area of reef?

Ibelieve the answer is a-broad because that is a leafed plant.

By water evaporation from the leaves is created a negative pressure at the top of the tree that promotes the ascension  of the water through channels that are called xylem. there are also two molecule forces that are involved: the intra-water molecules cohesion (water molecules stick to each other) and the adhesion when the water molecules stick to the channels they are running in. this is what enables water to go from the roots to the top of a tall tree.

Im not sure if you still need this but the answer is 300 hz450 hz  i just did this lesson so , wish you the best of luck and take care

Yes yes yes very good