[Grammar] Which transition words are proper in the blanks?

[wotcha22]

"Long-distance travel is easier than ever, thanks to the continued expansion of the airline industry. Unfortunately, there’s a downside to this trend: the more we travel, the more we add to our carbon footprint. That is, the airplanes that transport us release huge amounts of the greenhouse gas carbon dioxide, which is responsible for global warming. 1)_______________Several airlines, recognizing this fact, have begun to take action. 2)_______________fuel efficiency of aircraft is being increased, and planes are spending less time lined up on the runway waiting to take off. In addition, some airlines are adopting a policy of carbon offsetting, in which passengers are asked to pay a voluntary carbon fee for flights. This income is used to fund green campaigns that combat global warming."

Hi teachers! What transitions do you think would fit to the blanks?

I think 'However' and 'For example' can be used but my fellow teacher said 'So' and 'For example' are better.

:roll:

 

[Tdol]

I would use However, and several should be lower case.

 

[emsr2d2]

I don't like "however" at all in that context. I would expect it to introduce something like "However, several airlines have chosen to ignore this fact and start up dozens of new routes every year". I don't think anything should go before "Several airlines, recognising this fact ...".

"For example" is fine in the second space.

 

[Tdol]

Therefore would be OK.