Which activity might to increase the validity of this experiment? 1) repeating the experiment several times 2) using two different types of euglena in each tank 3) using the same concentration of nitrate solution in each tank 4) placing the euglena tank in darkness

1. 1 mole of anything contains 6.022x10^23 pieces  

d  

2. a  

3. c, number  

5. 1.24x10^24atoms / 6.022x10^23atoms/mole = 2moles h2 atoms  

6. fe2br3 mass = 2moles x mass fe + 3 moles x mass br  

molar mass = grams / number of moles = g/mole  

to find moles = g / molar mass  

to find mass = g = molar mass / moles

answer; i do believe the correct answer is (river); /// good luck