What is the main problem associated with metal refining?

it is extremely dangerous.
it does not produce very much refined metal.
it generates a great deal of waste.
it uses up a great deal of energy.

lizards have adapted to life in the desert. some desert lizards have toes with spiny scales to them run across the sand without sinking. some use the sand to hide from predators, or to search for small animals that they prey upon.

multiplying and dividing the two decimals and the eqations by the same number of the overalls