Why should you check the fabric grain when purchasing clothing

Ihave a really high metabolism and only weigh 70 pounds (13 almost 14). people always ask me two questions: do you ever eat and how do you eat so much and stay so skinny.i am worried that a high metabolism wont me forever. what are some safe steps i can take to maintain being fit. (also, i already work out i am a dancer so i get cardio a lot)

Diagram the passage of food through the digestive system. label the organs involved in digestion and absorption and identify the sites where carbohydrates, proteins, and fats are digested.

Iwill mark you brainlest if you answer this question