1.
When the jet rose six miles high,
it was clear the earth was round
and that it had more sea than land.
But it was difficult to understand

The noun form of 'difficult' is
2.
When the jet rose six miles high,
it was clear the earth was round
and that it had more sea than land.
But it was difficult to understand

From the height of the jet, the earth
3.
When the jet rose six miles high,
it was clear the earth was round
and that it had more sea than land.
But it was difficult to understand

From that height the poet saw that
4.
When the jet rose six miles high,
it was clear the earth was round
and that it had more sea than land.
But it was difficult to understand

The passage has been taken from :
5.
When the jet reached ten thousand feet,
it was clear why the country
had cities where the rivers ran
and why the valleys were populated.

The word 'valley' means the same as
6.
When the jet reached ten thousand feet,
it was clear why the country
had cities where the rivers ran
and why the valleys were populated.

The valleys are populated because
7.
When the jet reached ten thousand feet,
it was clear why the country
had cities where the rivers ran
and why the valleys were populated.

The cities are developed
8.
When the jet reached ten thousand feet,
it was clear why the country
had cities where the rivers ran
and why the valleys were populated.

From the height of ten thousand feet the poet was observing
9.
When the jet sprang into the sky,
it was clear why the city
had developed the way it had,
seeing it scaled six inches to the mile.

The word 'scaled' in the passage means :
10.
When the jet sprang into the sky,
it was clear why the city
had developed the way it had,
seeing it scaled six inches to the mile.

The city appeared from the sky