Answer:
I am heavy forward, but backward I'm not. What am I?
There's a one-story house in which everything is green. Green walls green windows green doors. What color are the stairs?
What is black when you buy it, red when you use it, and gray when you throw it away?
I have fangs and enjoy piecing holes with a single bite.
I am an odd number. Take away a letter and I become even. What number am I?
It has no top or bottom, but it can hold flesh, bones, and blood all at the same time.