Which is another name for observations?

inferences

data

predictions

models

explanation:

on disadvantage of hydroelectric power is the cost. another disadvantage of using hydroelectric power is finding a water source powerful enough to harvest hydroelectric power.

chert is a sedimentary rock composed of microcrystalline or cryptocrystalline silica. with this little bit of information, you can come to the conclusion that your answer is c.  

explanation:

igneous rocks which formed by the crystallization of magma at the surface of the earth called extrusive rocks. they are characterized by fine-grained textures because the rapid cooling at or near the surface did not provide enough time for large crystals to grow.

the cost of mining is extremely low compared to the money earned from mining, creating income to improve the environment.