I feel like this question is very troll but my guess is for less weight to hold them down....
D is the answer for your question
Hey! You can improve and maintain good health of an elementary school age child by making sure they get regular enjoyable exercise, have proper healthy balanced meals, and that they are learning and interacting with others their own age well. I wish you all good health and positive energy! :) - Aspen
They are all made of tissue and cells.
