How many significant figures are in the measurement 50.003010 nm?

This aquarium exhibits biotic and abiotic factors in an aquatic environment. one of the abiotic factors is

Aragonite shells of clams, snails, or scleractinian corals may be preserved unaltered in cenozoic deposits, but they are generally dissolved or recrystallized in older deposits. true or false

Which of these is the best source of stem cells and minimizes the risk with cell transplantation