Use the drop-down menus to complete the statements.
investigations allow for the control of variables and can be repeated.
investigations are usually less time-consuming and less expensive.
investigations make it possible to study a wide range of variables

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