This actually talks about the difference in the gas emission in the past and the current time. in 1990s the livestocks emission which means the gas emitted as a pollutant was in great amount untill 1990 but reduced afterward. however do you due to the beef cattle number it started again rising ( the emission of pollutant from livestock) the beef cattle number was increasing as the sheep were less in number. So the sheep was replaced by selling of cattle beef.
The other part of the sentence talks that if we reduce the useless domestic animal which is not very useful it will help to take down the emission. So it focus on saying to replace by animal or livestock which will yield or give profit and is high in nutrition so the gas emission reduces.
Read the passage. Create a begging sentence that's gonna grab the reader's attention. write a beginning middle and end and a finishing sentence explaining what you just wrote.
