The answer is A, 'a mammal' because it goes with the copulative verb 'to be', i. e., 'is'.
Answer:
a. bubbles formed
Explanation:
Bubbles are a sign of gaseous molecules escaping, meaning that something has forced molecules to break apart and escape. A chemical reaction involves any change that directly impacts the molecular formation of a substance.
I believe the correct answer among the choices listed above is option A. Parasitism is the kind of interaction that is shown here. Parasitism is a kind of relationship where one feed off the other. Fleas here are referred to as the parasite and the dog is the host.