Which of these is not a challenge an organism encounters

What does the mass of 0.7891 mol of ferric oxide (fe2o3)

The reactions shown here can be combined to make the overall reaction c(s) + h2o(g) ⇌ co(g) + h2(g) by reversing some and/or dividing all the coefficients by a number. a. c(s) + o2(g) → co2(g) k=1.363×10^69 b. 2 h2(g) + o2(g) → 2 h2o(g) k=1.389×10^80 c. 2co(g) + o2 (g) → 2 co2(g) k=1.477×10^90

When a device is used in a circuit in which the voltage is 81 v the current flowing through the device is 3 a what is the resistance of the device