Answer:
The non-excludability of public goods makes it difficult to profit
from them.
The most important question he couldn't answer is in fact how do organisms evolve. He knew that they evolve over a period of time but didn't know how it occurs and many after couldn't answer it either. Some even stipulated that evolution occurs through use or disuse of organs and the body develops around that, but they couldn't fully understand how it worked.
Safavid=Iran
Ottoman=turkey
Mughal=India
Containment ship was the preventing to spread communism and brinkmanship was a foreign policy strategy and nuclear diplomacy