Answer:
Air, everywhere, salt, and in the cold
Explanation:
A) a common ancestor
Homologous structures are structures that are similar in related organisms. There is a basic pattern of bones which can be inherited from a common ancestor
The correct answer is: the short half-life of edrophonium makes it impractical for long-term.
Edrophonium is used for the diagnostic of myasthenia gravis. In patient with myasthenia gravis, the body produces autoantibodies which inhibit nicotinic acetylcholine receptors in the neuromuscular junction. Edrophonium, on the other hand, is acetylcholinesterase inhibitor which blocks the effect of acetylcholinesterase enzymes (AcH stays in synaptic cleft).
Substitution for the edrophonium is pyridostigmine which is also acetylcholinesterase inhibitor but with long-term maintenance.