At the site of gas exchange in the lungs, where does the oxygen move?

O2 moves from the alveoli to the white blood cells.
O2 moves from the white blood cells to the alveoli.
O2 moves from the alveoli to the red blood cells.
O2 moves from the red blood cells to the alveoli.

1) these are barrel shaped microtubules in most animal cells, that organize the spindles during cell division

Consider the reaction of a(g) + b(g) + c(g) => d(g) for which the following data were obtained: experiment initial [a], mol/l initial [b], mol/l initial [c], mol/l initial rate, mol/l.s 1 0.0500 0.0500 0.0100 6.25 x 10^-3 2 0.100 0.0500 0.0100 2.50 x 10^-2 3 0.100 0.100 0.0100 1.00 x 10^-1 4 0.0500 0.0500 0.0200 6.25 x 10^-3 what is the rate law for the reaction?

How many moles of lead are in 1.50 x 10^12 atoms of lead? could you explain the answer as well and not just give it to me i am refreshing for finals and i need to know how to do it