Most wood floats in water but samples of wood called ebony can sink. based on the reading, what would you say about the density of this sinking wood compared to the density of water?

Floating and Sinking is based on the density of each material.

The more dense objects sink to the bottom, while the less dense objects float to the top.

Since the ebony sinks, it can be concluded that the density of ebony is greater than the density of water.

i'd say that the moon rock is about 2.2 billion years old.

well, that's easy; the answer's c, "it reduces contamination of the water and substrate of the estuary."