Writing Feedback / The number of people who opt to live alone are increasing in many countries around the world [4]

Hi! there's a wide range of vocabulary and sentence structures in your essay. Here are my suggestions, hope it'll be helpful:

+ the number of people .... is increasing ...
+ reach their decisions by on their own
+ many adults find it hard when ...
+ Living with the others may be ...
+ but people should consider about it rather ....

Writing Feedback / Today more people are overweight than ever before. What's are the primary causes of this? [6]

hello, here are some of my suggestions. Hope this helps:

+ people are becoming obese is that because they are ...
+ which includes the high amount of fat, sugar, and carbs in fact of instead of eating healthy food.
+ ... one of the most critical/serious/.... problems that affects plenty of people today ( you should have an adjective before the word "problem")

Also, I think it's better to add "according to a recent research study/survey/...." when you give this information: "For example, about more than 50%... "