In dialogue, you should start a new paragraph every time

a new speaker says something.

a question gets asked.

a decision gets made.

a speaker insults someone else.

People can make sacrifices like not going somewhere even when they want to, or not eating a certain food, or skipping something for a friend or family member. you can determine it yourself when you are thinking about what to do, such as: do you really want to go to the (input whatever) lets just say zoo, or do you want to your friend study so she can go to the dance next friday? (input whatever)the value in making sacrifices is being a true friend or family member, and seeing how it will affect others. it is very important!

Throughout the letter, the author makes his stance on urban sprawl very clear. the first example is in the first paragraph:

"urban sprawl, the spreading of large developments of housing and shopping areas around a city’s center, has many negative cultural and environmental effects. " (from your link)

so, your answer is: it has a negative effect on the environment, otherwise known as c~hope this mate.