Not exactly. There was an exact line. Anything below that line would be slave states. Anything above would not.
Answer:
C.To formally declare the colonists as an independent country
Is this all the information the question gave you?
Answer:
The "grave danger" that the author is talking about is the danger of atomic weaponry
Explanation:
"Preliminary Statement of the Association of Manhattan District Scientists" was a 100-page report written after the atomic bombings in Hiroshima and Nagasaki.
The "grave danger" that the scientist is talking about in the article is the dangers of atomic weaponry. The article talks about the consequences that wrong decisions of leaders may have on its nations.
Answer:
The speed of the airplane is approximately 770 km/h (214 m/s).
Explanation:
Speed = 
Distance = 3080 km
Time = 4 hours
speed = 
= 770
speed = 770 km/h
The speed of the airplane is 770 km/h.
OR
Distance = 3080 km
But,
1 000 m = 1 km
3080 km = 3080000 m
distance = 3080000 m
Time = 4 hours
60 seconds = 1 minute
60 minutes = 1 hour
Thus, 4 hours = 60 x 60 x 4
= 14400 seconds
Therefore,
speed = 
= 213.8889
speed ≅ 214 m/s
The speed of the airplane is approximately 214 m/s.
