Some people do not think interior design is an important part of life.
Please look at the sentence above. The 'interior design' does not have a definite article in the sentence. Should I put 'the' in front of it? If I do not place anything in front of it, is it still correct?
In addition, please look at the end of the sentence. Should 'part of life' be 'part of their lives'? Or is 'part of life' still correct? If so, what makes 'part of life' and 'part of their lives' different to each other?