Which two characteristics do all animals have?
o they are symmetrical and heterotrophic
o they are heterotrophs and have a backbone.
o their cells have a nucleus and membrane-bound organelles.
o they have a backbone, and their cells have membrane-bound organelles.

The answer is the third option "Their cells have a nucleus and membrane-bound organelles." All animals have cells and each cell has a nucleus the organelle that controls all of the other organelles, and the cell membrane which protects the cell. Just like how all plant cells have a cell wall to protect the cell.

Hope this helps.

c. heat from the poles back down towards the equator.