The reason I have belly fat even though my body fat is low......... T.T

I became curious after reading some posts about exercise.

My weight is normal and my body fat isn't high, but

I've noticed that there are a lot of people who are particularly worried about their belly fat.

I have a similar feeling, so I became curious.

There is also talk that it is due to posture issues.

I also heard that it is because of muscle mass.

I want to know which part has the biggest impact.

I'm also curious about effective exercise methods.