Which of the following statements is true?

the mineral ores for gold and silver are commonly found in the earth's crust.

the mineral ores for gold and silver are rarely found in the earth's crust.

the mineral ores for gold and silver can be easily manufactured artificially.

the mineral ores for gold and silver are commonly found in the oceans

Why are carbon dioxide concentrations expected to increase? a carbon dioxide concentrations are expected to increase, because fossil fuel burning is expected to increase b. carbon dioxide concentrations are expected to increase, because of an increase in agriculture. c.carbon dioxide concentrations are expected to increase, because more land will have to be cleared for increasing populations and agricultural use. d. all of the above select the best answer from the choices provided mark this and return save and exit next submit submit