Answer:
I am heavy forward but backward I'm not.
What can fill a room but takes up no space?
Though not a plant I have leaves. though not a beast I have spine. Though many wouldn't need me I am more valuable than wine.
Tuesday, Sam and Peter went to a restaurant. After eating lunch, they paid the bill. Sam and Peter did not pay. Who did?
I am all around, yet to me you are half blind. Sunlight makes me invisible and difficult to find. What am I?
Give it food and it will live, give it water and it will die.