Select the correct answer. Which property of a substance can be determined using a pH indicator?
A acidity
B. boiling point
C density
D. electrical conductivity
E. thermal conductivity

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