Alocal industrial plant uses oil to run it's furnace and then utilizes the waste heat to convert water to steam to power a turbine. such a use of one fuel to create both heat and electricity is an example of otec cogeneration energy efficiency a fuel cell

The right option is OTEC

Ocean Thermal Energy Conversion (OTEC) uses the temperature difference between deep cool ocean water and warm tropical surface waters to produce electricity. Quantities of cold water that can be used for air conditioning is produced as a by-product.

oceans

indian ocean

pacific ocean

atlantic ocean

arctic ocean

southern ocean

if your own plato the answer is b. the fern transitioned from sporophyte generation to gametophyte generation.