How should the enthalpy of an intermediate step be manipulated when used to produce an overall chemical equation?

You use the hess's law to deal with this kind of problems, i believe options should be given but you could  multiply the enthalpy by –1 if the chemical equation is reversed in theory.

If you need 2 cups for 24 cookies, then 1 cup for 12 cookies yes?

4 dozen cookies is 48 cookies, so 48/12=4 cups
6 dozen = 6 cups
10 dozen = 10 cups.

For 4 dozen its 4 cups
6 dozen is 6 cups
120 is 10 cups

I’d have to say no because without oxygen in the water the fish would all be dead. so if you want to fish for dead fish, pick the ponds with the lowest oxygen concentrations.