Earth’s atmosphere, oceans, and continents began to form during the first several hundred years of (1 point) a. precambrian time b. the paleozoic c. the mesozoic era < - d. the cenozoic era 8. during the devonian period, animals that could live on land began to evolve. these animals still spent part of their lives in the water. what were these animals called? a. trilobites b. reptiles < - c. amphibians d. dinosaurs

the grams   of   barium that   are in   2.3 x 10^23   atoms of barium   is   52.4 g (answer c)

    calculation

mass = moles   of ba   x molar   mass of ba

  molar mass of ba from periodic table=   137.3 g/mol

  use the   avogadro's law   constant   to   calculate the moles of barium

  that   is     1 mole =   6.02   x 10^23 atoms

                    ? moles = 2.3 x 10^23   atoms

by cross   multiplication

=(1 mole   x 2.3x 10^23 atoms)   / 6.02   x10^23 atoms)=   0.382   moles

mass   is therefore = 137.3   g/mol x 0.382 mol = 52.4 ( answer c)

explanation:

the answer would be b i believe