What is the material called that covers landmasses. the material is made out of once-living animals and tiny bits of rocks?

Which ocean zone has the most abundant primary producer and why a) the abyssopelagic zone ,du to the absence of light and cold water temperatureb) the bathypelagic zone, due to the absence of light and cold water temperaturec) the mesopelagic zone ,due to uts high light availability and warm water temperature d) the epipelagic zone,due to its high light availability and warm water temperature

Astudent reacts 13 moles of iron with 21 moles of oxygen according to the following equation:

What is the measured amount of a product obtained from a chemical reaction?