Identify two potential improvements to the opal extraction process and explain how
these improvements could minimize harm to the environment

To protect all four receptacles on a branch circuit that surrounds a swimming pool, you would install which of the following configurations? a. gfci feed-through receptacle at the end of the load's circuit b. gfci-terminated receptacle at the beginning of the load's circuit c. gfci feed-through receptacle at the beginning of the load's circuit and the other receptacles connected to the load side of that receptacle d. gfci-terminated receptacle at each end of the load's circuit

What elements are found in the inner and out core of the earth? the correct layers of earth's interior from the top to the center? what is the unwanted material that is removed from a mine called? how much stronger is an earthquake that registers 5 on the richter as opposed to 2? what occurs at a convergence plate boundary? the majority of the the earth's rock what is the most common element found in the earth's crust? what element is found in pyrite that contributes to acid mine drainage? why must mining companies post bond prior to permitting? how are bacteria being used in treating effluent from mines? what is a problem of acid mine drainage in rivers and soils? what do tectonic plates move on? why is gold smelting so damaging? how are artesian wells formed? where is dammed water colder than the river it flows into? what is one of the problems of uncontained aqueducts? what is the largest use of industrial water? underground sand and gravel formations that can store water? what type of water test measure acidity? which type of water test for cloudiness from suspended solids? what water test measures the amount of calcium and magnesium? these are all problems of coal power plants all of the following are advantages of riparian lands along rivers what type of water would be the warmest and have the least amount of dissolved oxygen? the zone of aeration is

Astudent creates a model of a closed ecosystem by filling a glass tank half full with water, then adding 10 snails and two small aquatic plants. the next day, all the snails are dead. what is the most likely cause of their death?