Q: Fact 1: Breathing is when a gill converts from oxygen in water into oxygen in blood. Fact 2: Many people confuse breathing with respiration, but breathing is just the first step of respiration. Given the two facts above, what is it when a gill converts from oxygen in water into oxygen in blood?

Select from the following.
a). fertilization occurs;
b). prolactin release;
c). preventing heat transfer;
d). first step of respiration;
e). last step of digestion;
f). flow of electrons;
g). death;
h). fish;
The answer is:
d).